如何将TextView绘制为位图(从未在显示器上绘制) [英] How to draw a TextView into a Bitmap (without ever being drawn on the display)
问题描述
根据将TextView截屏为位图"主题找到许多帖子.
Many posts are found according to the topic "screenshot a TextView into a Bitmap".
嗯,与我的问题不同的是,首先将视图绘制在显示器上(所有布局和测量工作已经完成),然后绘制到连接到位图的Canvas中.
Well, the difference to my problem is, that first the view is drawn on the display (with all layouting and measuring work already done) and then drawn into a Canvas connected to a Bitmap.
我只想从头开始创建一个TextView,而不会显示在渲染为位图的显示器上.
I just want to create a TextView from scratch without ever being shown on the display which is rendered into a Bitmap.
这是已经起作用的基本配置.单击TextView会将其自身绘制为位图,并将其设置为ImageView.
This one is the basis configuration which is already workin. A click on the TextView draws itself into a Bitmap and sets it to an ImageView.
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent" android:layout_height="fill_parent"
android:orientation="vertical" android:background="#fff">
<TextView android:id="@+id/tv" android:layout_width="wrap_content"
android:layout_height="wrap_content" android:text="The Quick Brown Fox Jumps Over The Lazy Dog."
android:textSize="20dip" android:background="#abcdef"
android:textColor="#000" android:padding="10dip"
android:layout_margin="10dip" />
<ImageView android:id="@+id/iv" android:layout_width="449px"
android:layout_height="47px" android:background="#56789a"
android:layout_margin="10dip" />
</LinearLayout>
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
findViewById(R.id.tv).setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
Bitmap bmp = Bitmap.createBitmap(449, 47, Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(bmp);
v.draw(canvas);
ImageView iv = (ImageView) findViewById(R.id.iv);
iv.setImageBitmap(bmp);
}
});
}
现在是有问题的部分.我将用Java创建一个TextView,并希望将其直接绘制到Bitmap中.之后,我将其设置为ImageView.我从来没有跑过:(
Now comes the problematic part. I will create a TextView in Java and I want this one to be drawn straight into a Bitmap. After this I will set this to an ImageView. I never got this running :(
Bitmap bmp = Bitmap.createBitmap(449, 47, Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(bmp);
TextView tv = new TextView(this);
tv.setText("THE QUICK BROWN FOX JUMPS OVER THE LAZY DOG");
tv.setTextSize(55f);
tv.setTextColor(this.getResources().getColor(android.R.color.black));
tv.draw(canvas);
ImageView iv = (ImageView) findViewById(R.id.iv);
iv.setImageBitmap(bmp);
这在onCreate或OnClickListener中均不起作用.使用setDrawingCacheEnabled(),measure()和requestLayout()也不起作用.
This doesn't work neither in onCreate nor in a OnClickListener. Experimenting with setDrawingCacheEnabled(), measure() and requestLayout() didn't work either.
推荐答案
有两种方法可以将TextView绘制到属于视图或从位图派生的画布中:
Here are two methods how to draw a TextView into canvas which belongs to a view or it is derived from a bitmap:
//method 1
TextPaint tp = new TextPaint(TextPaint.ANTI_ALIAS_FLAG);
tp.setColor(Color.WHITE);
tp.setTextSize(30);
tp.setShadowLayer(5, 2, 2, Color.CYAN);
StaticLayout sl=new StaticLayout("This is the first sample text
which will be wrapped within the text box.",tp,300,
Layout.Alignment.ALIGN_NORMAL, 1f,0f,false);
canvas.save();
canvas.translate(50, 20); //position text on the canvas
sl.draw(canvas);
canvas.restore();
//method 2
TextView textView = new TextView(StartActivity.this);
textView.layout(0, 0, 300, 500); //text box size 300px x 500px
textView.setTextSize(TypedValue.COMPLEX_UNIT_PX, 30);
textView.setTextColor(Color.WHITE);
textView.setShadowLayer(5, 2, 2, Color.CYAN); //text shadow
textView.setText("This is the second sample
text which will be wrapped within the text box.");
textView.setDrawingCacheEnabled(true);
canvas.drawBitmap(textView.getDrawingCache(), 50, 200, null);
//text box top left position 50,50
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