Android自己定義視圖（一）：帶底線的TextView

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package com.francis.underlinetextviewtest;import android.content.Context;import android.content.res.Resources;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.util.AttributeSet;import android.util.Log;import android.util.TypedValue;import android.widget.TextView;/** * Created by Francis on 14-10-13. */public class UnderlineTextView extends TextView {    private final Paint mPaint = new Paint();    private int mUnderlineHeight = 0;    public UnderlineTextView(Context context) {        this(context, null);    }    public UnderlineTextView(Context context, AttributeSet attrs) {        this(context, attrs, 0);    }    public UnderlineTextView(Context context, AttributeSet attrs, int defStyle) {        super(context, attrs, defStyle);        init(context, attrs);    }    private void init(Context context, AttributeSet attrs) {        Resources r = getResources();        // mUnderlineHeight == 6        mUnderlineHeight = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 2, r.getDisplayMetrics());    }    @Override    public void setPadding(int left, int top, int right, int bottom) {        super.setPadding(left, top, right, bottom + mUnderlineHeight);    }    @Override    protected void onDraw(Canvas canvas) {        super.onDraw(canvas);        // Draw the underline the same color as the text        mPaint.setColor(getTextColors().getDefaultColor());        // 對角線上的兩點。
        canvas.drawRect(0, getHeight() - mUnderlineHeight, getWidth(), getHeight(), mPaint);    }}

加入布局檔案：

<com.francis.underlinetextviewtest.UnderlineTextView        android:text="@string/hello_world"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:textStyle="bold"        android:textColor="#FFDDDDDD"/>

Android自己定義視圖（一）：帶底線的TextView