Android 操作UI线程的一些方法

  我们经常会在后台线程中去做一些耗时的操作,比如去网络取数据。但是当数据取回来,需要显示到页面上的时候,会遇到一些小麻烦,因为我们都知道,android的UI页面是不允许在其他线程直接操作的。下面总结4中方法用来在线程中操作UI界面。

  模拟耗时操作

private void connectNet() throws InterruptedException {
        Thread.sleep(2000);
}

  方法一:Handler

子线程中通过Handler的sendMessage(msg)发送事件:

private void method1() {
    new Thread(new Runnable() {
        @Override
        public void run() {
            try {
                //耗时操作
                connectNet();
                //向Handler发送消息
                mHadndler.sendEmptyMessage(111);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }).start();
}

  方法二:View.post(Runnable)

private void method2() {
    myText.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            new Thread(new Runnable() {
                @Override
                public void run() {
                    try {
                        //耗时操作
                        connectNet();
                        myText.post(new Runnable() {
                            @Override
                            public void run() {
                                myText.setText("联网结束,更新UI数据");
                            }
                        });
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
            }).start();
        }
    });
}

  方法三:Activity.runOnUiThread

与view.post类似

private void method3() {
    new Thread(new Runnable() {
        @Override
        public void run() {
            try {
                //耗时操作
                connectNet();
                runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        myText.setText("runOnUiThread...");
                    }
                });
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }).start();
}

    方法四:AsyncTask

private void method4() {
    //UI线程中执行
    new LoadTask().execute("www.91dota.com");
}
private class LoadTask extends AsyncTask {
    protected void onPostExecute(String result) {
        myText.setText(result); //得到来自网络的信息刷新页面
    }
    protected String doInBackground(Object[] objects) {
        return "......";//后台耗时操作
    }
}

 

===========================》

附上代码和布局

MainActivity.java

public class MainActivity extends AppCompatActivity {
    private TextView myText;
    private Handler mHadndler = new Handler() {
        @Override
        public void handleMessage(Message msg) {
            super.handleMessage(msg);
            myText.setText("收到消息啦..." + msg.what);
        }
    };

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        myText = findViewById(R.id.myTextView);
    }

    /**
     * 方法一:Handler
     */
    private void method1() {
        new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    //耗时操作
                    connectNet();
                    //向Handler发送消息
                    mHadndler.sendEmptyMessage(111);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }).start();
    }

    /**
     * 方法二:通过View.post(Runnable)
     */
    private void method2() {
        myText.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                new Thread(new Runnable() {
                    @Override
                    public void run() {
                        try {
                            //耗时操作
                            connectNet();
                            myText.post(new Runnable() {
                                @Override
                                public void run() {
                                    myText.setText("联网结束,更新UI数据");
                                }
                            });
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        }
                    }
                }).start();
            }
        });
    }

    /**
     * 方法三:Activity.runOnUiThread(Runnable )
     */
    private void method3() {
        runOnUiThread(new Runnable() {
            @Override
            public void run() {
                try {
                    //耗时操作
                    connectNet();
                    myText.setText("runOnUiThread...");
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        });
    }

    /**
     * 方法四:AsyncTask
     */
    private void method4() {
        //UI线程中执行
        new LoadTask().execute("www.91dota.com");

    }
    private class LoadTask extends AsyncTask {
        protected void onPostExecute(String result) {
            myText.setText(result); //得到来自网络的信息刷新页面
        }
        protected String doInBackground(Object[] objects) {
            return "......";//后台耗时操作
        }
    }

    private void connectNet() throws InterruptedException {
        Thread.sleep(2000);
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <TextView
        android:id="@+id/myTextView"
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:layout_margin="10dp"
        android:background="#dea"
        android:gravity="center"
        android:text="Hello World!" />

</LinearLayout>

参考:http://www.it165.net

关键词:void new android 操作 private mytext public override 方法 runnable

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