imageview上的DrawText

Question

我试着用这种方式写课文，但它不起作用，我不知道我哪里错了。

mImageView.buildDrawingCache();
Bitmap bmap = mImageView.getDrawingCache();
Canvas c = new Canvas (bmap);


Paint paint = new Paint();
paint.setColor(Color.RED); 
paint.setStyle(Style.FILL);                
paint.setTextSize(20);
c.drawText("Some Text", 0, 25, paint);

我尝试了几次，但显示器不能显示任何文本。我必须确保此图像随后与书面文本一起保存。谢谢

Answer 1

下面是如何在ImageView上绘制文本的简单示例：

MainActivity.java

package com.exmple.imagetest;

import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Paint.Style;
import android.os.Bundle;
import android.widget.ImageView;

public class MainActivity extends Activity {

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

        ImageView mImageView = (ImageView)findViewById(R.id.imageView1);

        Bitmap bm = BitmapFactory.decodeResource(getResources(), R.drawable.image);

        Config config = bm.getConfig();
        int width = bm.getWidth();
        int height = bm.getHeight();

        Bitmap newImage = Bitmap.createBitmap(width, height, config);

        Canvas c = new Canvas(newImage);
        c.drawBitmap(bm, 0, 0, null);

        Paint paint = new Paint();
        paint.setColor(Color.RED); 
        paint.setStyle(Style.FILL);                
        paint.setTextSize(20);
        c.drawText("Some Text", 0, 25, paint);

        mImageView.setImageBitmap(newImage);

    }

}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

    <ImageView
        android:id="@+id/imageView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_centerVertical="true"
        android:src="@drawable/image"
        android:contentDescription="@string/image" />

</RelativeLayout>

Answer 2

你可以试试，我用了一个很简单的技巧。我创建了一个包含ImageView和TextView的外部FrameLayout，如下所示：

 <FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent">

<ImageView  
    android:layout_width="fill_parent" 
    android:layout_height="fill_parent" 

    android:scaleType="center"
    android:src="@drawable/image" />

<TextView
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:layout_marginBottom="20dip"
    android:layout_gravity="center_horizontal|bottom"
    android:background="#9F000000"
    android:textColor="#ffffffff"
    android:text="+10" />

​

结果如下：

​