[Android UI开发] Android进行异步更新UI的四种方式

来源：互联网发布：美团数据分析专员编辑：程序博客网时间：2024/06/05 11:41

大家都知道由于性能要求，android要求只能在UI线程中更新UI，要想在其他线程中更新UI，我大致总结了4种方式，欢迎补充纠正：

使用Handler消息传递机制；
使用AsyncTask异步任务；
使用runOnUiThread(action)方法；
使用Handler的post(Runnabel r)方法；

下面分别使用四种方式来更新一个TextView。

1.使用Handler消息传递机制

packagecom.example.runonuithreadtest;
importandroid.app.Activity;
importandroid.os.Bundle;
importandroid.os.Handler;
importandroid.widget.TextView;
publicclassMainActivity extendsActivity {
    privateTextView tv;
    Handler handler = newHandler()
    {
        publicvoidhandleMessage(android.os.Message msg) {
            if(msg.what==0x123)
            {
                tv.setText("更新后的TextView");
            }
        };
    };
    @Override
    protectedvoidonCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        tv = (TextView) findViewById(R.id.tv);
        newMyThread().start();
    }
    classMyThread extendsThread
    {
        @Override
        publicvoidrun() {
            //延迟两秒更新
            try{
                Thread.sleep(2000);
            } catch(InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            handler.sendEmptyMessage(0x123);
        }
    }
}

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2. 使用AsyncTask异步任务

注：更新UI的操作只能在onPostExecute(String result)方法中。

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packagecom.example.runonuithreadtest;
importandroid.app.Activity;
importandroid.os.AsyncTask;
importandroid.os.Bundle;
importandroid.widget.TextView;
publicclassMainActivity extendsActivity {
    privateTextView tv;
    @Override
    protectedvoidonCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        tv = (TextView) findViewById(R.id.tv);
        newYibu().execute();
    }
    classYibu extendsAsyncTask<String, String, String>
    {
        @Override
        protectedString doInBackground(String... params) {
            try{
                Thread.sleep(2000);
            } catch(InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            returnnull;
        }
        @Override
        protectedvoidonPostExecute(String result) {
            // TODO Auto-generated method stub
            tv.setText("更新后的TextView");
        }
    }
}

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3. 使用runOnUiThread(action)方法

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packagecom.example.runonuithreadtest;
importandroid.app.Activity;
importandroid.os.Bundle;
importandroid.widget.TextView;
publicclassMainActivity extendsActivity {
    privateTextView tv;
    @Override
    protectedvoidonCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        tv = (TextView) findViewById(R.id.tv);
        newMyThread().start();
    }
    classMyThread extendsThread
    {
        @Override
        publicvoidrun() {
            runOnUiThread(newRunnable() {
                @Override
                publicvoidrun() {
                    // TODO Auto-generated method stub
                        try{
                            //延迟两秒更新
                            Thread.sleep(2000);
                        } catch(InterruptedException e) {
                            e.printStackTrace();
                        }
                        tv.setText("更新后的TextView");
                }
            });
        }
    }
}

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4. 使用Handler的post(Runnabel r)方法

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packagecom.example.runonuithreadtest;
importandroid.app.Activity;
importandroid.os.Bundle;
importandroid.os.Handler;
importandroid.widget.TextView;
publicclassMainActivity extendsActivity {
    privateTextView tv;
    @Override
    protectedvoidonCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        tv = (TextView) findViewById(R.id.tv);
        Handler handler = newHandler();
        handler.post(newRunnable(){
            @Override
            publicvoidrun() {
                try{
                    //延迟两秒更新
                    Thread.sleep(2000);
                } catch(InterruptedException e) {
                    e.printStackTrace();
                }
                tv.setText("更新后的TextView");
            }
        });
    }
}

原文 http://segmentfault.com/a/1190000003702775

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