Android~AsyncTask下载进度条demo

使用AsyncTask实现下载进度条效果

public class AsyncTaskActivity extends Activity implements View.OnClickListener {
    
    
    private Button mBtnStart;
    private Button mBtnCancel;
    private TextView mTVShow;
    private ProgressBar mProgress;
    private MyAsyncTask myAsyncTask;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
    
    
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_asynctask);
        initView();
    }

    private void initView() {
    
    
        mBtnStart = findViewById(R.id.btnStart);
        mBtnCancel = findViewById(R.id.btnCancel);
        mTVShow = findViewById(R.id.textShow);
        mProgress = findViewById(R.id.progress);
        myAsyncTask = new MyAsyncTask();

        mBtnStart.setOnClickListener(this);
        mBtnCancel.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
    
    
        switch (v.getId()) {
    
    
            case R.id.btnStart:
                myAsyncTask.execute();
                break;
            case R.id.btnCancel:
                myAsyncTask.cancel(true);
                break;
            default:
                break;
        }
    }

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

        @Override
        protected void onPreExecute() {
    
    
            super.onPreExecute();
            mTVShow.setText("加载中....");
        }

        @Override
        protected String doInBackground(String... strings) {
    
    
            int count = 0;
            while (count < 99) {
    
    
                count += 1;
                // 可调用publishProgress（）显示进度, 之后将执行onProgressUpdate（）
                publishProgress(count);
                try {
    
    
                    Thread.sleep(1 * 50);
                } catch (InterruptedException e) {
    
    
                    e.printStackTrace();
                }
            }
            return null;
        }

        @Override
        protected void onProgressUpdate(Integer... progresses) {
    
    
            super.onProgressUpdate(progresses);
            mProgress.setProgress(progresses[0]);
            mTVShow.setText("loading...." + progresses[0] + "%");
        }

        @Override
        protected void onPostExecute(String s) {
    
    
            super.onPostExecute(s);
            // 执行完毕后，则更新UI
            mTVShow.setText("加载完毕");
        }

        @Override
        protected void onCancelled() {
    
    
            super.onCancelled();
            mTVShow.setText("已取消加载");
            mProgress.setProgress(0);
        }
    }
}

<Button
     android:id="@+id/btnStart"
     android:layout_width="wrap_content"
     android:layout_height="wrap_content"
     android:text="开始加载" />

<TextView
     android:id="@+id/textShow"
     android:layout_width="wrap_content"
     android:layout_height="wrap_content"
     android:text="还没开始加载" />

<ProgressBar
     android:id="@+id/progress"
     style="?android:attr/progressBarStyleHorizontal"
     android:layout_width="match_parent"
     android:layout_height="wrap_content"
     android:max="100"
     android:progress="0" />

<Button
     android:id="@+id/btnCancel"
     android:layout_width="wrap_content"
     android:layout_height="wrap_content"
     android:text="取消加载" />