Some methods of Android operating UI thread

　　We often do some time-consuming operations in background threads, such as fetching data from the network. However, when the data is retrieved and needs to be displayed on the page, there will be some troubles, because we all know that the UI page of android is not allowed to be directly operated in other threads. The following summarizes the 4 methods used to operate the UI interface in the thread.

　　Simulate time-consuming operations

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

　　Method 1: Handler

In the child thread, the event is sent through the Handler's sendMessage (msg):

private void method1() {
    new Thread(new Runnable() {
        @Override
        public  void run() {
             try {
                 // Time -consuming operation 
                connectNet();
                 // Send message to Handler 
                mHadndler.sendEmptyMessage(111 );
            } catch (InterruptedException e) {
                e.printStackTrace ();
            }
        }
    }).start();
}

　　Method 2: 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 {
                         // time-consuming operation 
                        connectNet();
                        myText.post(new Runnable() {
                            @Override
                            public void run() {
                                myText.setText( "End of networking, update UI data" );
                            }
                        });
                    } catch (InterruptedException e) {
                        e.printStackTrace ();
                    }
                }
            }).start();
        }
    });
}

　　Method 3: Activity.runOnUiThread

Similar to view.post

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

　   Method 4: AsyncTask

private  void method4() {
     // execute new LoadTask().execute("www.91dota.com" ) in UI thread
    
}
private class LoadTask extends AsyncTask {
    protected void onPostExecute(String result) {
        myText.setText(result); // Get the information from the network to refresh the page 
    }
     protected String doInBackground(Object[] objects) {
         return "..."; // Background time-consuming operation 
    }
}

 

===========================》

Attach the code and layout

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( "Received a message..." + msg.what);
        }
    };

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

    /**
     * Method 1: Handler
     */
    private void method1() {
        new Thread(new Runnable() {
            @Override
            public  void run() {
                 try {
                     // Time -consuming operation 
                    connectNet();
                     // Send message to Handler 
                    mHadndler.sendEmptyMessage(111 );
                } catch (InterruptedException e) {
                    e.printStackTrace ();
                }
            }
        }).start();
    }

    /**
     * Method 2: Through 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 {
                             // time-consuming operation 
                            connectNet();
                            myText.post(new Runnable() {
                                @Override
                                public void run() {
                                    myText.setText( "End of networking, update UI data" );
                                }
                            });
                        } catch (InterruptedException e) {
                            e.printStackTrace ();
                        }
                    }
                }).start();
            }
        });
    }

    /**
     * Method 3: Activity.runOnUiThread (Runnable)
     */
    private void method3() {
        runOnUiThread(new Runnable() {
            @Override
            public  void run() {
                 try {
                     // time-consuming operation 
                    connectNet();
                    myText.setText("runOnUiThread...");
                } catch (InterruptedException e) {
                    e.printStackTrace ();
                }
            }
        });
    }

    /**
     * Method 4: AsyncTask
     */ 
    private  void method4() {
         // execute new LoadTask().execute("www.91dota.com" ) in UI thread
        

    }
    private class LoadTask extends AsyncTask {
        protected void onPostExecute(String result) {
            myText.setText(result); // Get the information from the network to refresh the page 
        }
         protected String doInBackground(Object[] objects) {
             return "..."; // Background time-consuming operation 
        }
    }

    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>

Reference: http://www.it165.net