android:How to detect when an Android app goes to the background and come back to the foreground

app-foreground-background-listen

You can detect when your whole application come to foreground and background using this very simple logic and for all android API level.

Usage

• You can use with any android API level.
• Create a BaseActivity for all Activity in your application.
• You can also use onStart() and onStop() of method of Activty seperately from BaseActivity.

public class BaseActivity extends Activity {

public void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);
    setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
}

public static boolean isAppInFg = false;
public static boolean isScrInFg = false;
public static boolean isChangeScrFg = false;

@Override
protected void onStart() {
    if (!isAppInFg) {
        isAppInFg = true;
        isChangeScrFg = false;
        onAppStart();
    } else {
        isChangeScrFg = true;
    }
    isScrInFg = true;

    super.onStart();
}

@Override
protected void onStop() {
    super.onStop();

    if (!isScrInFg || !isChangeScrFg) {
        isAppInFg = false;
        onAppPause();
    }
    isScrInFg = false;
}


public void onAppStart() {
    //remove this toast
    Toast.makeText(getApplicationContext(), "App in foreground", Toast.LENGTH_LONG).show();
    // your code
}

public void onAppPause() {
    //remove this toast
    Toast.makeText(getApplicationContext(), "App in background", Toast.LENGTH_LONG).show();
    // your code
}

}

• Now use this BaseActivity as a super class of all you Activity like MainActivity extends BaseActivity and onAppStart will be called when you starts your app and onAppPause() will be called when app goes background from any screen.