Question

我正在尝试动态更新主线程中的android LinearLayout。

不幸的是，我在网上教程中查明任何内容时遇到了很多麻烦。他们似乎都没有提供如何在线程之间进行通信的完整图片。

我的想法是这样的：

public class MainActivity extends AppCompatActivity {

    private LinearLayout layout;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        layout = new LinearLayout(this);
        setContentView(layout);

        Updater updater = new Updater();
        Thread workerThread = new Thread(updater);
        //somehow update layout

更新程序类看起来像这样：

public class Updater implements Runnable {

    private int count = 0;

    public Updater() {}

    @Override
    public void run()
    {
        for (int i = 0; i < 10; i ++){

            try {
                count++;
                TimeUnit.SECONDS.sleep(3);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }
}

我知道我需要Handler才能在线程之间传递消息，但我不知道如何设置它。

我想避免使用匿名类，并在TextView有新消息时动态创建新的Updater。

Answer 1

创建WorkerThreadListener界面：

public interface WorkerThreadListener {
    void onUpdate(int counter);
}

更改您的Updater课程：

public class Updater implements Runnable {

    private final WorkerThreadListener mWorkerThreadListener;
    private final Handler mHandler;

    private int count = 0;

    public Updater(final WorkerThreadListener workerThreadListener) {
        this.mWorkerThreadListener = workerThreadListener;
        this.mHandler = new Handler();
    }

    @Override
    public void run() {
        for (int i = 0; i < 10; i++) {
            try {
                count++;
                mHandler.post(new Runnable() {
                    @Override
                    public void run() {
                        mWorkerThreadListener.onUpdate(count);
                    }
                });
                TimeUnit.SECONDS.sleep(3);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }
}

更改MainActivity课程：

public class MainActivity extends AppCompatActivity {

    private LinearLayout layout;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        layout = new LinearLayout(this);
        setContentView(layout);
        Updater updater = new Updater(new WorkerThreadListener() {
            @Override
            public void onUpdate(int counter) {
                //update layout here
            }
        });
        Thread workerThread = new Thread(updater);
        workerThread.start();
    }
}

Answer 2

嗨，请检查我的下面的答案希望它可以帮到你。

public class ProgressTestActivity extends Activity {
    private ProgressBar progress;
    private TextView text;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        progress = (ProgressBar) findViewById(R.id.progressBar1);
        text = (TextView) findViewById(R.id.textView1);

    }

    public void startProgress(View view) {
        // do something long
        Runnable runnable = new Runnable() {
            @Override
            public void run() {
                for (int i = 0; i <= 10; i++) {
                    final int value = i;
                     doFakeWork();
                    progress.post(new Runnable() {
                        @Override
                        public void run() {
                           // here you can add any view or anyof your logic which is related to UI put it into here.
                            text.setText("Updating");
                            progress.setProgress(value);
                        }
                    });
                }
            }
        };
        new Thread(runnable).start();
    }

    // Simulating something timeconsuming
    private void doFakeWork() {
        SystemClock.sleep(5000);e.printStackTrace();
    }

}

其他方式也是可能的。如果您有任何疑问，请在下面发表评论我会详细解释您。

Answer 3

如果您只想使用滴答计时器并将进度设置为ui线程。您可以使用CountDownTimer。

public class MainActivity extends AppCompatActivity implements View.OnClickListener {
private TextView textView;
private CountDownTimer countDownTimer;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_new);
    textView = (TextView) findViewById(R.id.textView);
    findViewById(R.id.b2).setOnClickListener(this);
}

public void processData() {
    countDownTimer = new CountDownTimer(30000, 1000) {
        public void onTick(long millisUntilFinished) {
            textView.setText("seconds remaining: " + millisUntilFinished / 1000);
        }

        public void onFinish() {
            textView.setText("done!");
        }

    }.start();
}

@Override
protected void onStop() {
    super.onStop();
    if (countDownTimer != null) {
        countDownTimer.cancel();
    }
}

@Override
public void onClick(View v) {
    processData();
}
}

除了在UI线程上发布回调之外，您还可以使用Handler。

 Handler mainThreadHandler = new Handler(Looper.getMainLooper());
    mainThreadHandler.post(new Runnable() {
        @Override
        public void run() {

        }
    });

从新的Runnable类

3 个答案: