在 onCreate 中从 TextLayout 获取位图-移动开发问题

Getting Bitmap from TextLayout in onCreate(在 onCreate 中从 TextLayout 获取位图)

本文介绍了在 onCreate 中从 TextLayout 获取位图的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

只要事件发生在 after onCreate().但是当我尝试期间创建时，它不起作用.

有没有办法让它工作?我尝试过以各种方式使用 inflate()，但没有任何乐趣.

有各种已回答的问题，包括

公共类 MainActivity 扩展 AppCompatActivity {私有静态最终字符串 TAG = MainActivity.class.getSimpleName();私有RelativeLayout mTextLayout；@覆盖protected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);//这就是我想要的工作替换机器人()；//失败.位图为空.}公共无效 onClickGetBitmap(查看视图){替换机器人()；//工作.位图代替机器人.}私人无效替换机器人(){mTextLayout = (RelativeLayout) findViewById(sampleRelativeLayout);mTextLayout.setDrawingCacheEnabled(true);位图位图 = mTextLayout.getDrawingCache();如果(位图==空){Toast.makeText(getApplicationContext(), "位图为空", Toast.LENGTH_LONG).show();Log.v(TAG, "位图为空");}别的 {Toast.makeText(getApplicationContext(), "位图大小:" + bitmap.getWidth() +", " + bitmap.getHeight(), Toast.LENGTH_LONG).show();ImageView imageViewRobot = (ImageView) findViewById(R.id.imageViewRobot);imageViewRobot.setImageDrawable(new BitmapDrawable(this.getResources(), bitmap));}}}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?><RelativeLayout 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:id="@+id/activity_main_layout"android:layout_width="match_parent"android:layout_height="match_parent"android:paddingBottom="@dimen/activity_vertical_margin"android:paddingLeft="@dimen/activity_horizontal_margin"android:paddingRight="@dimen/activity_horizontal_margin"android:paddingTop="@dimen/activity_vertical_margin"工具:context=".MainActivity"><相对布局android:id="@+id/sampleRelativeLayout"android:layout_width="50dp"android:layout_height="50dp"><文本视图android:layout_width="wrap_content"android:layout_height="wrap_content"android:text="你好世界！"android:id="@+id/helloTextView"/></相对布局><图像视图android:layout_width="wrap_content"android:layout_height="wrap_content"应用程序:srcCompat="@mipmap/ic_launcher"android:id="@+id/imageViewRobot"android:layout_centerVertical="true"android:layout_centerHorizontal="true"/><按钮android:text="获取位图"android:onClick="onClickGetBitmap"android:layout_width="wrap_content"android:layout_height="wrap_content"android:layout_alignParentTop="true"android:layout_centerHorizontal="true"android:id="@+id/按钮"/></相对布局>

解决方案

View 尚未渲染.您可以使用 view.getViewTreeObserver().addOnGlobalLayoutListener 在布局准备就绪时获得通知.

所以，是这样的:

@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);最终 ViewTreeObserver viewTreeObserver = findViewById(sampleRelativeLayout).getViewTreeObserver();viewTreeObserver.addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {@覆盖公共无效 onGlobalLayout() {viewTreeObserver.removeOnGlobalLayoutListener(this);替换机器人()；}});}

I am able to convert a Layout with a TextView into a Bitmap, as long as the event that happens after onCreate(). But when I try during on create, it does not work.

Is there a way to get this to work? I have tried using inflate() in various ways with no joy.

There are various answered questions including this one that address the technique that I'm successfully using in my code. But the success does not include employing the technique from onCreate().

public class MainActivity extends AppCompatActivity {
    private static final String TAG = MainActivity.class.getSimpleName();

    private RelativeLayout mTextLayout;

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

        // This is what I would like to work
        replaceTheRobot(); // Fails.  Bitmap is null.
    }

    public void onClickGetBitmap(View view) {
        replaceTheRobot(); // Works.  Bitmap replaces the robot.
    }

    private void replaceTheRobot() {
        mTextLayout = (RelativeLayout) findViewById(sampleRelativeLayout);
        mTextLayout.setDrawingCacheEnabled(true);
        Bitmap bitmap = mTextLayout.getDrawingCache();
        if (bitmap == null) {
            Toast.makeText(getApplicationContext(), "The bitmap was null", Toast.LENGTH_LONG).show();
            Log.v(TAG, "The bitmap was null");
        }
        else {
            Toast.makeText(getApplicationContext(), "The bitmap size: " + bitmap.getWidth() +", " + bitmap.getHeight(), Toast.LENGTH_LONG).show();
            ImageView imageViewRobot = (ImageView) findViewById(R.id.imageViewRobot);
            imageViewRobot.setImageDrawable(new BitmapDrawable(this.getResources(), bitmap));
        }
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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:id="@+id/activity_main_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity">

    <RelativeLayout
        android:id="@+id/sampleRelativeLayout"
        android:layout_width="50dp"
        android:layout_height="50dp">
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Hello World!"
            android:id="@+id/helloTextView" />
    </RelativeLayout>

    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:srcCompat="@mipmap/ic_launcher"
        android:id="@+id/imageViewRobot"
        android:layout_centerVertical="true"
        android:layout_centerHorizontal="true" />

    <Button
        android:text="Get Bitmap"
        android:onClick="onClickGetBitmap"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:id="@+id/button" />
</RelativeLayout>

解决方案

View is not rendered yet. You can use view.getViewTreeObserver().addOnGlobalLayoutListener to get notified when your layout is ready.

So, something like this:

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    final ViewTreeObserver viewTreeObserver = findViewById(sampleRelativeLayout).getViewTreeObserver();
    viewTreeObserver.addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
        @Override
        public void onGlobalLayout() {
        viewTreeObserver.removeOnGlobalLayoutListener(this);
        replaceTheRobot();
        }
    });
}

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