Question

我正在尝试在textView上执行子类。它不会起作用。当我将类从textView扩展到View时。有用。但我需要TextView的功能。

但我无法在onDraw（）例程中执行任何drawLine或drawBitmap。但drawText（）和drawColor（）可以工作。我不明白为什么。

我无法找到onDraw（）的任何问题。有人能告诉我，我做错了什么吗？或者TextView不允许绘制位图或线条？下面是我的代码

package com.name.name;

import android.content.Context;

import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Paint.Align;
import android.graphics.Typeface;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.widget.TextView;

public class RDisplay extends TextView {
    Paint p;
    private String mName = "";
    private static Bitmap mImage = null;
    Context mContext;

    public RDisplay (Context context) {
        super(context);
        mContext = context;
        initComponent();

    }

    public RDisplay (Context context, AttributeSet attrs) {
        super(context, attrs);
        mContext = context;
        initComponent();
    }

    public void initComponent()
    {
        p = new Paint();
        p.setTextSize(30);
        p.setColor(Color.WHITE);

    }
    public void setName(String name)
    {
        mName = name;

        String file = "f_" + name.toLowerCase();
            Drawable d = mContext.getResources().getDrawable(R.drawable.image);
        mImage = ((BitmapDrawable)d).getBitmap();
        invalidate();
    }
    @Override
    protected void onDraw(Canvas canvas) {
        //super.onDraw(canvas);

        Paint paint = new Paint();
        paint.setStrokeWidth(20);
        paint.setColor(Color.WHITE);
        // drawText() Working
        canvas.drawText(mName, 0, getMeasuredHeight(), paint); 
        // drawLine() Not Working
        canvas.drawLine(0, 0, getMeasuredWidth(), getMeasuredHeight(), paint); 

        if(mImage != null)
        {   canvas.drawColor(Color.BLACK); //Working
            canvas.drawBitmap(mImage, 10, 10, null); // Not working
        }
    }

    void setFont(String fontName)
    {
        Typeface font = Typeface.createFromAsset(mContext.getAssets(), fontName); 
        setTypeface(font); 
    }
}

Answer 1

看起来您实际上从未实际调用setName(String)，mImage为空。另外，我很好的做法不在绘制中创建绘画。在初始化方法中创建它们并根据需要进行设置。

DrawLine或DrawBitmap在TextView的onDraw中不起作用

1 个答案: