android在子线程中更新数据

朴灿烈づ我的快乐病毒、 2022-07-14 14:00 276阅读 0赞

handler和runOnUiThred()方法更新。直接使用Thread异步线程不能更新view。

public class ReadActivity extends AppCompatActivity {
        private TextView show_txt;
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_read);
            setShow_txt();
        }
        private void setTitle(){
            new Common_title(this).setTitle(file_name)
                    .getBack().setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    finish();
                }
            });
        }
        //读取文件内容
        private void setShow_txt(){
            new Thread(new Runnable() {
                @Override
                public void run() {
                    try {
                        File file = new File(file_name);
                       
                        FileInputStream fis = new FileInputStream(file);
                        InputStreamReader isr = new InputStreamReader(fis);
                        BufferedReader bfr = new BufferedReader(isr);
                        String line;
                        StringBuilder respnse = new StringBuilder();
                        while ((line = bfr.readLine()) != null){
                            //读取数据
                            respnse.append(line+"\n");
                            //Log.i("line",line);
                        }
                        bfr.close();
                        isr.close();
                        fis.close();
                        //runOnUiThread更新UI
                        updateUI(respnse.toString());
    
                        //Hanlder更新UI
                        Message message = new Message();
                        message.what = 1;
                        Bundle bundle = new Bundle();
                        bundle.putString("key",respnse.toString());
                        message.setData(bundle);
                        handler.sendMessage(message);
    
                        //Hanlder.post更新UI
                        handerUpdataUI(respnse.toString());
                    } catch (FileNotFoundException e) {
                        e.printStackTrace();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
            }).start();
    
        }
        //子线程更新UI 方法1
        private void updateUI(final String resonse){
            runOnUiThread(new Runnable() {
                @Override
                public void run() {
                    show_txt.setText(resonse);
                }
            });
        }
        //子线程更新UI 方法2
        private Handler handler = new Handler(){
            @Override
            public void handleMessage(Message msg) {
                switch (msg.what){
                    case 1:
                        //处理信息
                        show_txt.setText(msg.getData().getString("key"));
                        break;
                }
            }
        };
        //子线程更新UI 方法3
        private void handerUpdataUI(final String resonse){
            handler.post(new Runnable() {
                @Override
                public void run() {
                    show_txt.setText(resonse);
                }
            });
            //延迟更新
            //handler.postDelayed()
            //定时更新
            //handler.postAtTime()
        }
    }