android按返回完全退出程序,Android防误按返回退出程序

1、按返回时弹出退出提示

@Override

public boolean onKeyDown(int keyCode, KeyEvent event) {

// TODO Auto-generated method stub

Log.e("OtherActivity", "onKeyDown, keyCode: "+keyCode);

if (keyCode == KeyEvent.KEYCODE_BACK) {

ShowExitTooltip(OtherActivity.this);

return true;

}

return super.onKeyDown(keyCode, event);

}

public static void ShowExitTooltip(Context context) {

AlertDialog.Builder builder = new Builder(context);

builder.setMessage("确定要退出吗?");

builder.setTitle("提示");

builder.setIcon(android.R.drawable.ic_dialog_alert);

builder.setPositiveButton("确认",

new DialogInterface.OnClickListener() {

public void onClick(DialogInterface dialog, int which) {

dialog.dismiss();

android.os.Process.killProcess(android.os.Process.myPid());

}

});

builder.setNegativeButton("取消",

new android.content.DialogInterface.OnClickListener() {

public void onClick(DialogInterface dialog, int which) {

dialog.dismiss();

}

});

builder.create().show();

}

2、提示双击返回退出

A：利用Handler延迟发送更改状态信息

// 定义一个变量，来标识是否退出

private static boolean isExit = false;

Handler mHandler = new Handler() {

@Override

public void handleMessage(Message msg) {

super.handleMessage(msg);

isExit = false;

}

};

@Override

public boolean onKeyDown(int keyCode, KeyEvent event) {

if (keyCode == KeyEvent.KEYCODE_BACK) {

exit();

return false;

}

return super.onKeyDown(keyCode, event);

}

private void exit() {

if (!isExit) {

isExit = true;

Toast.makeText(getApplicationContext(), "双击退出程序", Toast.LENGTH_SHORT).show();

// 利用handler延迟发送更改状态信息

mHandler.sendEmptyMessageDelayed(0, 2000);

} else {

finish();

System.exit(0);

}

}

B：通过记录按键时间计算时间差实现

private long exitTime = 0;

@Override

public boolean onKeyDown(int keyCode, KeyEvent event) {

if (keyCode == KeyEvent.KEYCODE_BACK) {

exit();

return false;

}

return super.onKeyDown(keyCode, event);

}

public void exit() {

if ((System.currentTimeMillis() - exitTime) > 2000) {

Toast.makeText(getApplicationContext(), "双击退出程序", Toast.LENGTH_SHORT).show();

exitTime = System.currentTimeMillis();

} else {

finish();

System.exit(0);

}

}