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使用CountDownTimer更新ProgressBar



我正在尝试用AsyncTask和CountDownTimer更新ProgressBar。我没有错误，但ProgressBar没有更新。

由于MyDownloadTask扩展了AsyncTask，所以我不需要发布方法或onProgressUpdate()。我的ProgressBar在doInBackground((中自动更新。

我认为CountDownTimer中的代码没有执行，但我正在调用monCountTimer.start();

这里是我的Java代码：

public class myDownloadTask extends AsyncTask<Integer, Integer, String> {
public void setMonCountTimer(CountDownTimer monCountTimer) {
this.monCountTimer = monCountTimer;
}
public void setInc(int inc) {
this.inc = inc;
}
public void setMaProgressBar(ProgressBar maProgressBar) {
this.maProgressBar = maProgressBar;
}
public CountDownTimer getMonCountTimer() {
return monCountTimer;
}
public int getInc() {
return inc;
}
public ProgressBar getMaProgressBar() {
return maProgressBar;
}
protected CountDownTimer monCountTimer;
private int inc = 0;
protected ProgressBar maProgressBar;
public void setMonAct(MainActivity monAct) {
this.monAct = monAct;
}
public MainActivity getMonAct() {
return monAct;
}
private MainActivity monAct;

public myDownloadTask(ProgressBar maBarre, MainActivity monActi) {
this.maProgressBar = maBarre;
this.monAct = monActi;
}

@Override
protected void onPreExecute() {
super.onPreExecute();
this.maProgressBar.setProgress(0);
}
@Override
protected void onProgressUpdate(Integer... integers) {
super.onProgressUpdate(integers);
}
@Override
protected String doInBackground(Integer... integers) {
Thread monThread = new Thread(new Runnable() {
@Override
public void run() {
monCountTimer = new CountDownTimer(6000, 1000) {
@Override
public void onTick(long millisUntilFinished) {
myDownloadTask.this.inc++;
myDownloadTask.this.getMaProgressBar().setProgress((int) myDownloadTask.this.inc* 100 / (6000 / 1000));
}
@Override
public void onFinish() {
}
};
monCountTimer.start();
}
});
return "coucou";
}
}

主要类别：

public class MainActivity extends AppCompatActivity  {
private ProgressBar maBarre ;
public void setMaBarre(ProgressBar maBarre) {
this.maBarre = maBarre;
}
public void setLaunchAsync(Button launchAsync) {
this.launchAsync = launchAsync;
}
public void setMonHandler(Handler monHandler) {
this.monHandler = monHandler;
}
public void setMonCountTimer(CountDownTimer monCountTimer) {
this.monCountTimer = monCountTimer;
}
public void setMonTask(myDownloadTask monTask) {
this.monTask = monTask;
}
public void setProgressThread(Thread progressThread) {
ProgressThread = progressThread;
}
public void setI(int i) {
this.i = i;
}
public ProgressBar getMaBarre() {
return maBarre;
}
public Button getLaunchAsync() {
return launchAsync;
}
public Handler getMonHandler() {
return monHandler;
}
public CountDownTimer getMonCountTimer() {
return monCountTimer;
}
public String getPROGRESS_BAR_INCREMENT() {
return PROGRESS_BAR_INCREMENT;
}
public static int getMessagePreExecute() {
return MESSAGE_PRE_EXECUTE;
}
public static int getMessageProgressUpdate() {
return MESSAGE_PROGRESS_UPDATE;
}
public static int getMessagePostExecute() {
return MESSAGE_POST_EXECUTE;
}
public myDownloadTask getMonTask() {
return monTask;
}
public Thread getProgressThread() {
return ProgressThread;
}
public int getI() {
return i;
}
private Button launchAsync;
private Handler monHandler ;
private CountDownTimer monCountTimer ;
private final String PROGRESS_BAR_INCREMENT="ProgreesBarIncrementId";
private static final int MESSAGE_PRE_EXECUTE = 1;
private static final int MESSAGE_PROGRESS_UPDATE = 2;
private static final int MESSAGE_POST_EXECUTE = 3;
myDownloadTask monTask;
Thread ProgressThread ;
private int i = 0 ;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
maBarre = (ProgressBar) findViewById(R.id.progressBar);
launchAsync = (Button) findViewById(R.id.button);
setSupportActionBar(toolbar);

FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
this.launchAsync.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
monTask = new myDownloadTask(MainActivity.this.maBarre , MainActivity.this);
monTask.execute();

}
});
}


@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}

@Override
public void onPointerCaptureChanged(boolean hasCapture) {
}
}

你能帮我吗？

请为您的XML文件尝试此操作。我不知道你想达到什么样的布局，但当我做到"；setProgress(50("在onCreate中，没有使用发布的XML文件显示任何内容。

我创建了这个XML布局，现在进度条显示良好：

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
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">
<Button
android:id="@+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="8dp"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:text="Button"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/progressBar" />
<ProgressBar
android:id="@+id/progressBar"
style="?android:attr/progressBarStyleHorizontal"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="140dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<android.support.design.widget.FloatingActionButton
android:id="@+id/fab"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="bottom|end"
android:layout_margin="10dip"
android:layout_marginBottom="8dp"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/button"
app:srcCompat="@android:drawable/ic_dialog_email" />
</android.support.constraint.ConstraintLayout>

在onCreate中，添加：

ProgressBar bar = findViewById(R.id.progressBar);
bar.setProgress(50);

测试布局。。。

还有几个问题：线程已经创建，但之后必须调用start((。

monCountTimer.start();

在public void run((中，代码正在执行以下操作：

myDownloadTask.this.getMaProgressBar().setProgress((int) 
myDownloadTask.this.inc* 100 / (6000 / 1000));

永远不要从Android中的工作线程更新视图。所有视图都必须在"；主线程"；也称为"；UI线程"；

解决这个问题的一个快速方法是：

runOnUiThread(new Runnable() {
@Override
public void run() {
// ...
}
});

我已经做了上面的更改，现在运行良好：

public class MainActivity extends AppCompatActivity  {
private ProgressBar maBarre ;
public void setMaBarre(ProgressBar maBarre) {
this.maBarre = maBarre;
}
public void setLaunchAsync(Button launchAsync) {
this.launchAsync = launchAsync;
}
public void setMonHandler(Handler monHandler) {
this.monHandler = monHandler;
}
public void setMonCountTimer(CountDownTimer monCountTimer) {
this.monCountTimer = monCountTimer;
}
public void setMonTask(myDownloadTask monTask) {
this.monTask = monTask;
}
public void setProgressThread(Thread progressThread) {
ProgressThread = progressThread;
}
public void setI(int i) {
this.i = i;
}
public ProgressBar getMaBarre() {
return maBarre;
}
public Button getLaunchAsync() {
return launchAsync;
}
public Handler getMonHandler() {
return monHandler;
}
public CountDownTimer getMonCountTimer() {
return monCountTimer;
}
public String getPROGRESS_BAR_INCREMENT() {
return PROGRESS_BAR_INCREMENT;
}
public static int getMessagePreExecute() {
return MESSAGE_PRE_EXECUTE;
}
public static int getMessageProgressUpdate() {
return MESSAGE_PROGRESS_UPDATE;
}
public static int getMessagePostExecute() {
return MESSAGE_POST_EXECUTE;
}
public myDownloadTask getMonTask() {
return monTask;
}
public Thread getProgressThread() {
return ProgressThread;
}
public int getI() {
return i;
}
private Button launchAsync;
private Handler monHandler ;
private CountDownTimer monCountTimer ;
private final String PROGRESS_BAR_INCREMENT="ProgreesBarIncrementId";
private static final int MESSAGE_PRE_EXECUTE = 1;
private static final int MESSAGE_PROGRESS_UPDATE = 2;
private static final int MESSAGE_POST_EXECUTE = 3;
myDownloadTask monTask;
Thread ProgressThread ;
private int i = 0 ;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
maBarre = (ProgressBar) findViewById(R.id.progressBar);
launchAsync = (Button) findViewById(R.id.button);
//etSupportActionBar(toolbar);

FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
this.launchAsync.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
monTask = new myDownloadTask(MainActivity.this.maBarre , MainActivity.this);
monTask.execute();
}
});
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
// getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
return super.onOptionsItemSelected(item);
}

@Override
public void onPointerCaptureChanged(boolean hasCapture) {
}

public class myDownloadTask extends AsyncTask<Integer, Integer, String> {
public void setMonCountTimer(CountDownTimer monCountTimer) {
this.monCountTimer = monCountTimer;
}
public void setInc(int inc) {
this.inc = inc;
}
public void setMaProgressBar(ProgressBar maProgressBar) {
this.maProgressBar = maProgressBar;
}
public CountDownTimer getMonCountTimer() {
return monCountTimer;
}
public int getInc() {
return inc;
}
public ProgressBar getMaProgressBar() {
return maProgressBar;
}
protected CountDownTimer monCountTimer;
private int inc = 0;
protected ProgressBar maProgressBar;
public void setMonAct(MainActivity monAct) {
this.monAct = monAct;
}
public MainActivity getMonAct() {
return monAct;
}
private MainActivity monAct;

public myDownloadTask(ProgressBar maBarre, MainActivity monActi) {
this.maProgressBar = maBarre;
this.monAct = monActi;
}

@Override
protected void onPreExecute() {
super.onPreExecute();
this.maProgressBar.setProgress(0);
}
@Override
protected void onProgressUpdate(Integer... integers) {
super.onProgressUpdate(integers);
}
@Override
protected String doInBackground(Integer... integers) {
Thread monThread = new Thread(new Runnable() {
@Override
public void run() {
runOnUiThread(new Runnable() {
@Override
public void run() {
monCountTimer = new CountDownTimer(6000, 1000) {
@Override
public void onTick(long millisUntilFinished) {
myDownloadTask.this.inc++;
myDownloadTask.this.getMaProgressBar().setProgress((int) myDownloadTask.this.inc * 100 / (6000 / 1000));
}
@Override
public void onFinish() {
}
};
monCountTimer.start();
}
});
}
});
monThread.start();
return "coucou";
}
}
}

需要思考的几个问题：

  • 这里创建的线程比需要的要多，代码可以写得更简单。doInBackground已经在一个单独的线程上，因此不需要在其中创建另一个线程。此外，我相信CountDownTimer已经在自己的线程中运行了，所以这里的很多代码可能是不必要的
  • 当你完成开发后，去掉所有这些警告。软件开发实际上是关于纪律和良好的习惯，只有糟糕的开发人员才会忽视警告！做一个"；analy->检查代码"；当你做完的时候

但你的进度条更新程序现在对我来说很好。

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout 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"
tools:context=".MainActivity">
<android.support.design.widget.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:theme="@style/AppTheme.AppBarOverlay">
<android.support.v7.widget.Toolbar
android:id="@+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
app:popupTheme="@style/AppTheme.PopupOverlay" />
</android.support.design.widget.AppBarLayout>
<include layout="@layout/content_main" />
<android.support.design.widget.FloatingActionButton
android:id="@+id/fab"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="bottom|end"
android:layout_margin="@dimen/fab_margin"
app:srcCompat="@android:drawable/ic_dialog_email" />


</android.support.design.widget.CoordinatorLayout>

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout 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"
app:layout_behavior="@string/appbar_scrolling_view_behavior"
tools:context=".MainActivity"
tools:layout_editor_absoluteY="81dp"
tools:showIn="@layout/activity_main">
<Button
android:id="@+id/button"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="236dp"
android:text="Button"
app:layout_constraintEnd_toEndOf="@+id/progressBar"
app:layout_constraintHorizontal_bias="1.0"
app:layout_constraintStart_toStartOf="@+id/progressBar"
app:layout_constraintTop_toTopOf="parent" />
<ProgressBar
android:id="@+id/progressBar"
style="?android:attr/progressBarStyleHorizontal"
android:layout_width="200dp"
android:layout_height="40dp"
android:layout_marginBottom="336dp"
android:layout_marginEnd="104dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent" />
<android.support.constraint.ConstraintLayout
android:id="@+id/constraintLayout"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
</android.support.constraint.ConstraintLayout>
</android.support.constraint.ConstraintLayout>

好的，非常感谢！！！！(

我试过了：

@Override
protected String doInBackground(Integer... integers) {
Thread monThread = new Thread(new Runnable() {
@Override
public void run() {
monCountTimer = new CountDownTimer(6000, 1000) {
@Override
public void onTick(long millisUntilFinished) {
myDownloadTask.this.inc++;
myDownloadTask.this.getMaProgressBar().setProgress((int) myDownloadTask.this.inc* 100 / (6000 / 1000));
}
@Override
public void onFinish() {
}
};
monCountTimer.start();
}
monThread.start();
});
return "coucou";
}

有了这段代码，我的应用程序就崩溃了。

但有了runOnUiThread(new Runnable() {....}，它的工作原理是

我们使用2线程。。。；(它没有优化，3与monCountTimer，也许，我们可以删除monThread

"我相信CountDownTimer已经在自己的线程中运行了，所以这里的很多代码可能是不必要的。">

我试过：

@Override
protected String doInBackground(Integer... integers) {
monCountTimer = new CountDownTimer(6000, 1000) {
@Override
public void onTick(long millisUntilFinished) {
myDownloadTask.this.inc++;
myDownloadTask.this.getMaProgressBar().setProgress((int) myDownloadTask.this.inc * 100 / (6000 / 1000));
}
@Override
public void onFinish() {
}
};
monCountTimer.start();
}

它不起作用

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