Develop Reference

the android app crashes or not installs after building using android studio

When i run my app in my device [which runs on 7.1] The app runs well but when i run it on my opo which runs on 4.4 it crashed and when i try to run it on a android 5.0 device it gave app cannot install error
I've build>generate signed apk and have used that
I'm basically new to all this so if anyone can help me out what the issue is i would be glad
my activity_main code is
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.bingobean.pitchblack.MainActivity"
android:weightSum="1">
<ImageView
android:id="#+id/imageView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:scaleType="center"
android:src="#drawable/android"
android:layout_alignParentStart="true"
android:layout_alignParentTop="true" />
<TextView
android:id="#+id/textView"
android:layout_width="wrap_content"
android:layout_height="55dp"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="34dp"
android:text="Pitch black"
android:textColor="#ffffff"
android:textSize="50sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<Button
android:id="#+id/button"
android:layout_width="118dp"
android:layout_height="109dp"
android:layout_marginTop="144dp"
android:text="Hit it!"
android:textSize="24sp"
android:layout_below="#+id/textView"
android:layout_centerHorizontal="true" />
</RelativeLayout>
My mainactivity is
package com.bingobean.pitchblack;
import android.app.WallpaperManager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.Toast;
import java.io.IOException;
public class MainActivity extends AppCompatActivity {
Button btn;
ImageView img;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btn = (Button) findViewById(R.id.button);
img = (ImageView) findViewById(R.id.imageView1);
btn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
WallpaperManager wallmgr =
WallpaperManager.getInstance(getApplicationContext());
try {
wallmgr.setResource(+ R.drawable.android);
} catch (IOException e){
e.printStackTrace();
}
Toast.makeText(getApplicationContext(), "Wallpaper is set",
Toast.LENGTH_SHORT).show();
}
});
}
}
My Androidmanifest is
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.bingobean.pitchblack">
<uses-permission android:name="android.permission.SET_WALLPAPER"/>
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:roundIcon="#mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="#style/AppTheme">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>

check your app level build.gradle file in , in that file You have these two attributes :
minSdkVersion 16
targetSdkVersion 23 this
// these are api levels
Change them to according to your requirement .

Ditto to what Hamza said, you must have set your min and target api to not be compatible with kitkat. as for the app not installed, that is either 1: you have an app with same package name installed, 2: the LAUNCH and DEFAULT intents aren't set (they are it seems), or 3: it somehow got corrupted. Please post your logcat for when it crashes. Root your phone and download LogCat.

Osmdroid's MapView doesn't display map

Maps are not displayed =(. I use osmdroid libs to display them, and Samsung Tab 2 10.1" for debugging. I tryed to search the problem and most answers were: "you didn't add permission in ur manifest". I added all permissions, but maps, are still not displayed, I also saw, that when some emulators had no SD cards, maps weren't displayed, I have no SD card on my Tablet may be that is the reason. If it is so, what should I do to solve the problem, and if it's not, so what is the real problem then.
I got this main.java
package com.example.tradersamurai;
import org.osmdroid.DefaultResourceProxyImpl;
import org.osmdroid.ResourceProxy;
import org.osmdroid.tileprovider.tilesource.TileSourceFactory;
import org.osmdroid.util.GeoPoint;
import org.osmdroid.views.MapView;
import android.os.Bundle;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.view.Menu;
import android.widget.Button;
import android.view.View;
import android.widget.TextView;
public class MainActivity extends Activity
{
// Layout elements
Button btnAddMark;
Button btnShowPath;
TextView tvPathInfo;
MapView mapView;
//
CityGraph minimap;
#Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
// --------------------------------------------------------------------------------------------
btnAddMark = (Button) findViewById(R.id.btn_add_mark);
btnShowPath = (Button) findViewById(R.id.btn_show_path);
tvPathInfo = (TextView) findViewById(R.id.tv_path_info);
mapView = (MapView) findViewById(R.id.mapview);
mapView.setTileSource(TileSourceFactory.MAPNIK);
mapView.setBuiltInZoomControls(true);
mapView.setMultiTouchControls(true);
mapView.setUseDataConnection(true);
minimap = new CityGraph();
}
#Override
public boolean onCreateOptionsMenu(Menu menu)
{
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
public void btn_show_path_click(View v)
{
tvPathInfo.setText("show path");
}
public void btn_add_mark_on_click(View v)
{
if(minimap.get_size() + 1 > CityGraph.MAX_SIZE)
tvPathInfo.setText("Out of range");
else
{
minimap.add_new_vertex();
tvPathInfo.setText("Added OK");
}
}
}
my Manifest
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.tradersamurai"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="18" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-feature android:name="android.hardware.location.network" />
<uses-feature android:name="android.hardware.location.gps" />
<uses-feature android:name="android.hardware.wifi" />
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name="com.example.tradersamurai.MainActivity"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
and layout
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
tools:context=".MainActivity" >
<Button
android:id="#+id/btn_show_path"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/btn_add_mark"
android:layout_below="#+id/btn_add_mark"
android:layout_marginTop="24dp"
android:onClick="btn_show_path_click"
android:text="#string/btn_display_path_info_text" />
<Button
android:id="#+id/btn_add_mark"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_alignParentTop="true"
android:layout_marginRight="76dp"
android:layout_marginTop="35dp"
android:onClick="btn_add_mark_on_click"
android:text="#string/btn_add_mark_text" />
<TextView
android:id="#+id/tv_path_info"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/btn_show_path"
android:layout_below="#+id/btn_show_path"
android:layout_marginTop="46dp"
android:text="#string/tv_path_info" />
<org.osmdroid.views.MapView
android:id="#+id/mapview"
android:layout_width="800dp"
android:layout_height="fill_parent"
android:layout_centerVertical="true"
android:clickable="true" >
</org.osmdroid.views.MapView>
</RelativeLayout>

Getting my location on android 4.2.2

I am a beginner in android development. I was trying a very simple code to get my location through the device gps and post it in a textView. I am not having any errors though when I start the application on the emulator it fails to start and I get this message "unfortunately test1 has stopped ".
This is my manifest file:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.test1"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="18" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name="com.example.test1.MainActivity"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
`
this is my activity_main code :
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
tools:context=".MainActivity" >
<TextView
android:id="#+id/text"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/hello_world" />
This is my main_activity.class code :
package com.example.test1;
import android.location.Location;
import android.location.LocationManager;
import android.os.Bundle;
import android.app.Activity;
import android.content.Context;
import android.view.Menu;
import android.widget.TextView;
import android.widget.Toast;
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
TextView textView;
textView = (TextView) findViewById(R.id.text);
LocationManager manager =
(LocationManager)getSystemService(Context.LOCATION_SERVICE);
Location loc = manager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
textView.setText("latitude: " + loc.getLatitude()
+ "\nlongitude: " + loc.getLongitude());
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
Any help on making it work ??

Why can't I send an array of 1000000 ints from one Activity to another?

I'm trying to second an array of 1000000 ints from one Activity to another. It works fine with smaller numbers, but when I try 1000000, startActivity does nothing, and causes this to show in logcat:
E/JavaBinder(2239): !!! FAILED BINDER TRANSACTION !!!
Why?
Here's some code demonstrating the issue:
MainActivity.java
package com.example.a;
import android.os.Bundle;
import android.view.View;
import android.app.Activity;
import android.content.Intent;
public class MainActivity extends Activity {
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public void startSecond(View v) {
startActivity(new Intent(this, SecondActivity.class).putExtra(
"a", new int[1000000]));
}
}
SecondActivity.java
package com.example.a;
import android.os.Bundle;
import android.app.Activity;
public class SecondActivity extends Activity {
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_second);
}
}
activity_main.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity" >
<Button
android:id="#+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:layout_marginLeft="56dp"
android:layout_marginTop="31dp"
android:onClick="startSecond"
android:text="click clack" />
</RelativeLayout>
activity_second.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
</LinearLayout>
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.a"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="17" />
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name="com.example.a.MainActivity"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name="com.example.a.SecondActivity"></activity>
</application>
</manifest>

Why?
Because you are limited to 1MB per Binder transaction, and Binder underlies the Intent system. The size of your Intent, including all extras, needs to be under 1MB.

I Have Error a google map android api v2 is not loaded

I have a project of google map android api v2 but i run this project in my phone a logcat has error
Falied to load map.Error contacting Google servers. This is probable an authentication issue(but could be due to network errors)
so my code is Here
in class HomeActivity
package com.mpa.emvi;
import com.mpa.emvi.R;
import android.support.v4.app.FragmentActivity;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;
import android.os.Bundle;
//import android.app.Activity;
import android.view.Menu;
public class HomeActivity extends FragmentActivity {
private GoogleMap mMap;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_home);
setUpMapIfNeeded();
}
#Override
protected void onResume() {
super.onResume();
setUpMapIfNeeded();
}
private void setUpMapIfNeeded() {
// Do a null check to confirm that we have not already instantiated the map.
if (mMap == null) {
// Try to obtain the map from the SupportMapFragment.
mMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map))
.getMap();
// Check if we were successful in obtaining the map.
if (mMap != null) {
setUpMap();
}
}
}
private void setUpMap() {
mMap.addMarker(new MarkerOptions().position(new LatLng(0, 0)).title("Marker"));
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.home, menu);
return true;
}
}
this is a Layout HomeActivity
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/send"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
tools:context=".HomeActivity" >
<fragment xmlns:map="http://schemas.android.com/apk/res-auto"
android:id="#+id/map"
android:name="com.google.android.gms.maps.SupportMapFragment"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_centerHorizontal="true"/>
<Button
android:id="#+id/sendDS"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="#+id/map"
android:layout_centerHorizontal="true"
android:text="#string/send_destination"/>
</RelativeLayout>
And this is a Manifest File
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.mpa.emvi"
android:versionCode="2"
android:versionName="2.1.0">
<permission
android:name="com.mpa.emvi.permission.MAPS_RECEIVE"
android:protectionLevel="signature"/>
<uses-permission android:name="com.mpa.emvi.permission.MAPS_RECEIVE"/>
<!-- Copied from Google Maps Library/AndroidManifest.xml. -->
<uses-sdk
android:minSdkVersion="11"
android:targetSdkVersion="14"/>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="com.google.android.providers.gsf.permission.READ_GSERVICES"/>
<!-- External storage for caching. -->
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<!-- My Location -->
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
<!-- Maps API needs OpenGL ES 2.0. -->
<uses-feature
android:glEsVersion="0x00020000"
android:required="true"/>
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name="com.mpa.emvi.HomeActivity"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<meta-data android:name="com.google.android.maps.v2.API_KEY"
android:value="My-Release-API-KEY"/>
</application>
</manifest>
You see my code. What do you thing?
Ok I'm try to seach same issue in this and i try re-generate new api key but not work.
In my project aleady import a google service lib and android support v4.
In google console i open google map android api v2 service.
In google console android apps: my-SHA1-serials;com.mpa.emvi
OK a lasting I'm a newbie android programmer and sorry for my english is poor.
Thank for every Answer.

Have you added your Api key in Manifest File?

Ok now my app is showing the map.I forget delete old apk file and re-install new apk file it work.Thank For Any Answer Thank.