Android 退出APP应用常用方式

public boolean onKeyDown(int keyCode, KeyEvent event) {
switch (keyCode) {
case KeyEvent.KEYCODE_BACK://如果是返回键就做出判断
AlertDialog.Builder build = new AlertDialog.Builder(this);
build.setTitle("系统提示").setMessage("确定要退出吗？");
build.setPositiveButton("确定",
new DialogInterface.OnClickListener() {

@Override
public void onClick(DialogInterface dialog, int which) {
finish();
}
});
build.setNegativeButton("取消",
new DialogInterface.OnClickListener() {

@Override
public void onClick(DialogInterface dialog, int which) {
}
}).show();
break;
}
return super.onKeyDown(keyCode, event);
}

private long exitTime = 0;

@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK
&& event.getAction() == KeyEvent.ACTION_DOWN) {
if ((System.currentTimeMillis() - exitTime) > 2000) {
Toast.makeText(getApplicationContext(), "再按一次退出程序",
Toast.LENGTH_SHORT).show();
exitTime = System.currentTimeMillis();
} else {
finish();
System.exit(0);
}
return true;
}
return super.onKeyDown(keyCode, event);
}

这里写代码片

private void exitBy2Click(){
Timer tExit = null;
if (isExit == false) {
isExit = true; // 准备退出
T.showShort(this,R.string.again_according_to_exit_the_program);
tExit = new Timer();
tExit.schedule(new TimerTask() {
@Override
public void run() {
isExit = false; // 取消退出
}
}, 2000); // 如果2秒钟内没有按下返回键，则启动定时器取消掉刚才执行的任务

} else {
ActivityUtils.finishAll();//关闭所有界面
System.exit(0);
}
}