handler机制消息循环发送

Question

利用handler机制 每隔1s发送一次消息 不适用线程 仅利用handler和message

利用handler+message 模拟一个4分钟的加载进度条

Answer 1

public class Test {
    private static final int MESSAGE = 100;
    private int timerCount = 0;
    public Test() {
        handler.sendEmptyMessageDelayed(MESSAGE, 1000);
    }

    private final Handler.Callback callback = new Handler.Callback() {
        @Override
        public boolean handleMessage(@NonNull Message msg) {
            if (msg.what == MESSAGE) {
                if (timerCount >= 4 * 60)
                    return false;
                timerCount++;
                handler.sendEmptyMessageDelayed(MESSAGE, 1000);
            }
            return false;
        }
    };

    private final Handler handler = new Handler(Looper.getMainLooper(), callback);
}