自定义控件粗糙实现

values下新建attrs.xml：

<?xml version="1.0" encoding="UTF-8"?>
<resources>
    <declare-styleable name="FontView">

        <!-- Text to display. -->
        <attr name="text" format="string" localization="suggested" />
        <!-- <attr name="textColor" />
        <attr name="textSize" /> -->

    </declare-styleable>
</resources>

主界面xml：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <com.itant.fontdemo.FontView
        xmlns:fv="http://schemas.android.com/apk/res-auto"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        fv:text="我是瘦金体wafd" />

</LinearLayout>

MainActivity：

package com.itant.fontdemo;

import android.app.Activity;
import android.os.Bundle;

public class MainActivity extends Activity {

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

}

自定义View：

package com.itant.fontdemo;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Typeface;
import android.util.AttributeSet;
import android.view.View;

public class FontView extends View {

    private Paint mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
    private Typeface mTypeface;
    private String text;

    public FontView(Context context, AttributeSet attrs){
        super(context, attrs);
        mTypeface = Typeface.createFromAsset(getContext().getAssets(), "king.ttf");
        mPaint.setTextSize(52);

        TypedArray typedArray = context.obtainStyledAttributes(attrs, R.styleable.FontView);
        text = typedArray.getString(R.styleable.FontView_text);


        typedArray.recycle();
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        //super.onMeasure(widthMeasureSpec, heightMeasureSpec);

        // 可抽取为方法
        int height = 300;
        int specMode = MeasureSpec.getMode(heightMeasureSpec);
        int specSize = MeasureSpec.getSize(heightMeasureSpec);

        switch (specMode) {
        case MeasureSpec.AT_MOST:
            if (specSize < height) {
                height = specSize;
            }
            break;
        case MeasureSpec.EXACTLY:
            height = specSize;
            break;
        }

        setMeasuredDimension(getDefaultSize(getSuggestedMinimumWidth(), widthMeasureSpec), height);
    }

    @Override
    protected void onDraw(Canvas canvas){
        canvas.drawColor(Color.GRAY);
        mPaint.setTypeface(mTypeface);
        canvas.drawText(text, 10, 50, mPaint);
    }
}

其中assets/king.ttf是瘦金体的字体库。

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