android 点击返回键退出程序的方法
第一种： 再按一次返回键退出程序
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);
}
或者
private long exitTime = 0;
@Override
public boolean dispatchKeyEvent(KeyEvent event) {
if (event.getKeyCode() == KeyEvent.KEYCODE_BACK
&& event.getAction() == KeyEvent.ACTION_DOWN
&& event.getRepeatCount() == 0) {
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.dispatchKeyEvent(event);
}
另外一种：点击返回键弹出确定窗体 选择退出
@Override
public boolean dispatchKeyEvent(KeyEvent event) {
if (event.getKeyCode() == KeyEvent.KEYCODE_BACK
&& event.getAction() == KeyEvent.ACTION_DOWN
&& event.getRepeatCount() == 0) {
//详细的操作代码
new AlertDialog.Builder(this)
.setTitle("确定退出程序么")
.setNegativeButton("取消", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
}
})
.setPositiveButton("确定", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int whichButton) {
finish();//
}
}).show();
return true;
}
return super.dispatchKeyEvent(event);
}