back双击退出

安卓手机的back返回键 方法是OnkeyDown

private long exitTime;
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (keyCode==KeyEvent.KEYCODE_BACK){
if (System.currentTimeMillis() - exitTime > 2000 ){
Toast.makeText(this,"再次点击退出应用", Toast.LENGTH_SHORT).show();

localBroadcastManager.sendBroadcast(intent);
return true;
}else {
finish();
}
}
return super.onKeyDown(keyCode, event);
}


弹出对话框的退出

public long exitime;
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if(keyCode==KeyEvent.KEYCODE_BACK){
if (System.currentTimeMillis()-exitime>2000){
final AlertDialog.Builder builder = new AlertDialog.Builder(ZhuActivity.this);
builder.setTitle("是否要返回");
builder.setMessage("点击选择……");
builder.setNegativeButton("取消", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialogInterface, int i) {
dialog.cancel();
}
});
builder.setPositiveButton("确定", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialogInterface, int i) {
finish();
}
});
dialog= builder.create();
dialog.show();
}else{
}
}
return super.onKeyDown(keyCode, event);
}