如何将TextView绘制到位图中(无需在显示屏上绘制)

时间:2011-09-04 09:48:19

标签: android canvas bitmap textview

根据主题“将TextView截图到位图”中找到了很多帖子。

嗯,我的问题的不同之处在于,首先在显示器上绘制视图(已完成所有布局和测量工作),然后将其绘制到连接到位图的Canvas中。

我只是想从头开始创建一个TextView,而不会在显示器上显示,并将其渲染为位图。

这是已经有效的基础配置。单击TextView将自身绘制到Bitmap中并将其设置为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);
        }
    });
}

现在出现问题部分。我将在Java中创建一个TextView,我希望将其直接绘制到Bitmap中。在此之后,我将其设置为ImageView。我从没跑过这个:(

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和OnClickListener中都不起作用。尝试使用setDrawingCacheEnabled(),measure()和requestLayout()也不起作用。

1 个答案:

答案 0 :(得分:19)

以下是两种方法如何将TextView绘制到属于视图的canvas中,或者是从位图派生的:

//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