java - Android主线程与其他线程之间的通信

Question

我想动态更改 TextView 的文本，但如果我想创建一个游戏线程，我将需要相同的逻辑，因此我需要在主线程和第二个线程之间进行通信。

我有文件:

主要 Activity

public class MainActivity extends ActionBarActivity {

    public static Handler mHandler;
    Runnable thread = new SampleThread();
    TextView txt1 = (TextView) findViewById(R.id.txt1);
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        ActionBar actionBar = getSupportActionBar();
        actionBar.hide();

        //hiding status bar
        if (Build.VERSION.SDK_INT < 16) {
            getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
                    WindowManager.LayoutParams.FLAG_FULLSCREEN);
        } else {
            View decorView = getWindow().getDecorView();
            int uiOptions = View.SYSTEM_UI_FLAG_FULLSCREEN;
            decorView.setSystemUiVisibility(uiOptions);
        }
        setContentView(R.layout.activity_main);


        mHandler = new Handler() {
            public void handleMessage(Message msg) {
                // process incoming messages here
                // i want to change the text of txt1 here
            }
        };
        new Thread(thread).start();


    }
}

示例线程

package com.example.katsar0v.myapplication;

import android.util.Log;

/**
 * Created by Katsar0v on 1/21/2015.
 */
public class SampleThread implements Runnable {

    @Override
    public void run() {
        int two = 0;
        while(two<10) {
            two++;
            try {
                Thread.sleep(1000);

                //instead of logging, i want to send the text to main UI
                Log.d("MSG", String.valueOf(two + "sec"));
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }
}

我看到的问题是，当我的线程位于另一个文件中时，如何使用处理程序更改文本？或者我应该在第一个类中使第二个类静态(当代码变得很长时我应该做什么，它不能全部在一个文件中)？

Answer 1

您可以实现自定义Interface，以便从您的主要 Activity 中处理它。在您的 SampleThread 上:

public interface TextViewChangeListener
{
    public void onTextViewChanged(String newName);
}
TextViewChangeListener mListener;

然后，无论您希望在 TextView 中使用新名称，都可以调用 mListener.onTextViewChanged(String newName)。请记住首先使用 MainActivity 的实例初始化 mListener，否则您将收到空指针异常。您可以在 SampleThread 的构造函数中或通过为此目的创建一个方法来执行此操作。

在您的 Activity 中，您应该实现 SampleThread.TextViewChangeListener 并覆盖 onTextViewChanged。

@Override
public void onTextViewChanged(String newName)
{
   //MyTextView.setText(newName);
}

编辑:未经测试的代码:主要 Activity :

public class MainActivity extends ActionBarActivity implements SampleThread.TextViewChangeListener {
@Override
public void onTextViewChanged(Message msg)
{
    // process incoming messages here
    // i want to change the text of txt1 here
}

public static Handler mHandler;
Runnable thread = new SampleThread(this);
TextView txt1 = (TextView) findViewById(R.id.txt1);
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    ActionBar actionBar = getSupportActionBar();
    actionBar.hide();

    //hiding status bar
    if (Build.VERSION.SDK_INT < 16) {
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
                WindowManager.LayoutParams.FLAG_FULLSCREEN);
    } else {
        View decorView = getWindow().getDecorView();
        int uiOptions = View.SYSTEM_UI_FLAG_FULLSCREEN;
        decorView.setSystemUiVisibility(uiOptions);
    }
    setContentView(R.layout.activity_main);
    new Thread(thread).start();
}
}

示例线程:

package com.example.katsar0v.myapplication;
import android.util.Log; 
/**
* Created by Katsar0v on 1/21/2015.
*/
public class SampleThread implements Runnable 
{
public interface TextViewChangeListener
{
    public void onTextViewChanged(Message msg);
}

public SampleThread(TextViewChangeListener mListener)
{
    this.mListener = mListener;
}

TextViewChangeListener mListener;

@Override
public void run() {
    int two = 0;
    while(two<10) {
        two++;
        try {
            Thread.sleep(1000);
            mListener.onTextViewChanged(String.valueOf(two + "sec"));
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
}
}

请告诉我这是否有帮助。