在Android屏幕上显示加载叠加图 [英] Display a loading overlay on Android screen

问题描述

我希望在屏幕上显示一个叠加层，该叠加层显示一个小的加载行情栏，甚至可能包含一些文本，而我的应用程序尝试登录到服务器.我的登录屏幕全都在垂直线性布局内.

I'm looking to display an overlay over the screen that shows a little loading ticker or possibly even some text whilst my app attempts to log into the server. My login screen is all inside of a vertical linear layout.

我想要达到的效果是这样的: http://docs.xamarin. com/recipes/ios/standard_controls/popovers/display_a_loading_message

The effect I'm trying to achieve is something like this: http://docs.xamarin.com/recipes/ios/standard_controls/popovers/display_a_loading_message

推荐答案

也许为时已晚，但我想有人可能会发现它有用.

Maybe too late, but I guess somebody might find it useful.

活动:

public class MainActivity extends Activity implements View.OnClickListener {

    String myLog = "myLog";

    AlphaAnimation inAnimation;
    AlphaAnimation outAnimation;

    FrameLayout progressBarHolder;
    Button button;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        button = (Button) findViewById(R.id.button);
        progressBarHolder = (FrameLayout) findViewById(R.id.progressBarHolder);

        button.setOnClickListener(this);

    }

    @Override
    public void onClick(View v) {
        switch (v.getId()) {
            case R.id.button:
                new MyTask().execute();
                break;
        }

    }

    private class MyTask extends AsyncTask <Void, Void, Void> {

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            button.setEnabled(false);
            inAnimation = new AlphaAnimation(0f, 1f);
            inAnimation.setDuration(200);
            progressBarHolder.setAnimation(inAnimation);
            progressBarHolder.setVisibility(View.VISIBLE);
        }

        @Override
        protected void onPostExecute(Void aVoid) {
            super.onPostExecute(aVoid);
            outAnimation = new AlphaAnimation(1f, 0f);
            outAnimation.setDuration(200);
            progressBarHolder.setAnimation(outAnimation);
            progressBarHolder.setVisibility(View.GONE);
            button.setEnabled(true);
        }

        @Override
        protected Void doInBackground(Void... params) {
            try {
                for (int i = 0; i < 5; i++) {
                    Log.d(myLog, "Emulating some task.. Step " + i);
                    TimeUnit.SECONDS.sleep(1);
                }
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            return null;
        }
    }

}

布局xml:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Start doing stuff"
        android:id="@+id/button"
        android:layout_below="@+id/textView"
        android:layout_centerHorizontal="true" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceLarge"
        android:text="Do Some Stuff"
        android:id="@+id/textView"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true" />

    <FrameLayout
        android:id="@+id/progressBarHolder"
        android:animateLayoutChanges="true"
        android:visibility="gone"
        android:alpha="0.4"
        android:background="#000000"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <ProgressBar
            style="?android:attr/progressBarStyleLarge"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:indeterminate="true"
            android:layout_gravity="center" />
    </FrameLayout>
</RelativeLayout>

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