如何更新安卓UI

接下来介绍下几种安卓ui更新的方法
1.使用Handler的post(new Runnable())方法；

public class MainActivity extends AppCompatActivity {

    private TextView mTextView;

    private Handler handler = new Handler();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mTextView = (TextView) findViewById(R.id.text_view_handle_post);
        handler.post(new Runnable() {
            @Override
            public void run() {
                try {
                    Thread.sleep(2000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                mTextView.setText("子线程通过post方法更新后的UI");
            }
        });
    }
}

2.使用View的post(new Runnable())方法，其底层也是调用Handler.post(new Runnable())方法；

public class MainActivity extends AppCompatActivity {

    private TextView mTextView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mTextView = (TextView) findViewById(R.id.text_view_post);
        mTextView.post(new Runnable() {
            @Override
            public void run() {
                try {
                    Thread.sleep(2000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                mTextView.setText("子线程通过view.post方法更新后的UI");
            }
        });
    }
}

3.使用AsyncTask异步任务类

public class MainActivity extends AppCompatActivity {

    private TextView mTextView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mTextView = (TextView) findViewById(R.id.text_view_async_task);
        new MyAsyncTask().execute();
    }

    class MyAsyncTask extends AsyncTask<String, String, String> {

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
        }

        @Override
        protected String doInBackground(String... params) {
            try {
                Thread.sleep(2000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            String str = "子线程通过AsyncTask异步更新后的UI";
            // 返回结果给到onPostExecute方法
            return str;
        }

        @Override
        protected void onProgressUpdate(String... values) {
            super.onProgressUpdate(values);
        }

        @Override
        protected void onPostExecute(String result) {
            mTextView.setText(result);
            super.onPostExecute(result);
        }
    }
}

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