android Handler 基础知识入门

常见问题

This message is already in use.

08-12 12:02:42.678: E/AndroidRuntime(5417): android.util.AndroidRuntimeException: { when=-318ms what=0 arg1=1 target=com.tomchen.smsbomb.view.FastChangeTextView$1 } This message is already in use.


Solution


加上 msg = mHandler.obtainMessage();

[code]    @Override
    public void handleMessage(Message msg) {
        switch (msg.arg1) {

        case UPDATE:

            if (currentValue < value) {
                Log.i(tag, "in mHandler UPDATE CASE");
                setText(df.format(currentValue));
                currentValue = currentValue + rate;
                //add this line
                msg = mHandler.obtainMessage();
                msg.arg1 = UPDATE;

                sendMessageDelayed(msg, 30);
            } else {
                setText(df.format(value));
            }

            break;

        default:
            break;

        }
        super.handleMessage(msg);
    }

};

Handler 谷歌 官方文档学习

sendMessageDelayed 和sendEmptyMessageDelayed

sendMessageDelayed(Message msg, long delayMillis)


Enqueue a message into the message queue after all pending messages before (current time + delayMillis).

sendEmptyMessageDelayed(int what, long delayMillis)


Sends a Message containing only the what value, to be delivered after the specified amount of time elapses.

简单说, 就是sendMessageDelayed 发送 Message, sendEmptyMessageDelayed 发送一个只包含

what

的Message

上文把代码可以改成sendEmptyMessageDelayed


switch 也要改成从

what

取出标记值

[code]private Handler mHandler = new Handler() {

        @Override
        public void handleMessage(Message msg) {
            switch (msg.what) {

            case UPDATE:

                if (currentValue < value) {
                    setText(df.format(currentValue));
                    currentValue = currentValue + rate;
                    sendEmptyMessageDelayed(UPDATE, 30);
                } else {
                    setText(df.format(value));
                }

                break;

            default:
                break;

            }
            super.handleMessage(msg);
        }

    };

Note


sendEmptyMessageDelayed 不需要

obtainMessage()

如果文章对您有帮助，请多多支持^=^