Android 自己定义View (二) 进阶

转载请标明出处：http://blog.csdn.net/lmj623565791/article/details/24300125

继续自己定义View之旅。前面已经介绍过一个自己定义View的基础的样例，Android
自己定义View (一)，假设你还对自己定义View不了解能够去看看。今天给大家带来一个略微复杂点的样例。

自己定义View显示一张图片，以下包括图片的文本介绍，类似相片介绍什么的，只是不重要，主要是学习自己定义View的使用方法么。

还记得上一篇讲的4个步骤么:

1、自己定义View的属性

2、在View的构造方法中获得我们自己定义的属性

[ 3、重写onMesure ]

4、重写onDraw

直接切入正题：

1、在res/values/attr.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>

    <attr name="titleText" format="string" />
    <attr name="titleTextSize" format="dimension" />
    <attr name="titleTextColor" format="color" />
    <attr name="image" format="reference" />
    <attr name="imageScaleType">
        <enum name="fillXY" value="0" />
        <enum name="center" value="1" />
    </attr>

    <declare-styleable name="CustomImageView">
        <attr name="titleText" />
        <attr name="titleTextSize" />
        <attr name="titleTextColor" />
        <attr name="image" />
        <attr name="imageScaleType" />
    </declare-styleable>

</resources>

2、在构造中获得我们的自己定义属性：

/**
	 * 初始化所特有自己定义类型
	 *
	 * @param context
	 * @param attrs
	 * @param defStyle
	 */
	public CustomImageView(Context context, AttributeSet attrs, int defStyle)
	{
		super(context, attrs, defStyle);

		TypedArray a = context.getTheme().obtainStyledAttributes(attrs, R.styleable.CustomImageView, defStyle, 0);

		int n = a.getIndexCount();

		for (int i = 0; i < n; i++)
		{
			int attr = a.getIndex(i);

			switch (attr)
			{
			case R.styleable.CustomImageView_image:
				mImage = BitmapFactory.decodeResource(getResources(), a.getResourceId(attr, 0));
				break;
			case R.styleable.CustomImageView_imageScaleType:
				mImageScale = a.getInt(attr, 0);
				break;
			case R.styleable.CustomImageView_titleText:
				mTitle = a.getString(attr);
				break;
			case R.styleable.CustomImageView_titleTextColor:
				mTextColor = a.getColor(attr, Color.BLACK);
				break;
			case R.styleable.CustomImageView_titleTextSize:
				mTextSize = a.getDimensionPixelSize(attr, (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_SP,
						16, getResources().getDisplayMetrics()));
				break;

			}
		}
		a.recycle();
		rect = new Rect();
		mPaint = new Paint();
		mTextBound = new Rect();
		mPaint.setTextSize(mTextSize);
		// 计算了描绘字体须要的范围
		mPaint.getTextBounds(mTitle, 0, mTitle.length(), mTextBound);

	}

3、重写onMeasure

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

		/**
		 * 设置宽度
		 */
		int specMode = MeasureSpec.getMode(widthMeasureSpec);
		int specSize = MeasureSpec.getSize(widthMeasureSpec);

		if (specMode == MeasureSpec.EXACTLY)// match_parent , accurate
		{
			Log.e("xxx", "EXACTLY");
			mWidth = specSize;
		} else
		{
			// 由图片决定的宽
			int desireByImg = getPaddingLeft() + getPaddingRight() + mImage.getWidth();
			// 由字体决定的宽
			int desireByTitle = getPaddingLeft() + getPaddingRight() + mTextBound.width();

			if (specMode == MeasureSpec.AT_MOST)// wrap_content
			{
				int desire = Math.max(desireByImg, desireByTitle);
				mWidth = Math.min(desire, specSize);
				Log.e("xxx", "AT_MOST");
			}
		}

		/***
		 * 设置高度
		 */

		specMode = MeasureSpec.getMode(heightMeasureSpec);
		specSize = MeasureSpec.getSize(heightMeasureSpec);
		if (specMode == MeasureSpec.EXACTLY)// match_parent , accurate
		{
			mHeight = specSize;
		} else
		{
			int desire = getPaddingTop() + getPaddingBottom() + mImage.getHeight() + mTextBound.height();
			if (specMode == MeasureSpec.AT_MOST)// wrap_content
			{
				mHeight = Math.min(desire, specSize);
			}
		}
		setMeasuredDimension(mWidth, mHeight);

	}

4、重写onDraw

@Override
	protected void onDraw(Canvas canvas)
	{
		// super.onDraw(canvas);
		/**
		 * 边框
		 */
		mPaint.setStrokeWidth(4);
		mPaint.setStyle(Paint.Style.STROKE);
		mPaint.setColor(Color.CYAN);
		canvas.drawRect(0, 0, getMeasuredWidth(), getMeasuredHeight(), mPaint);

		rect.left = getPaddingLeft();
		rect.right = mWidth - getPaddingRight();
		rect.top = getPaddingTop();
		rect.bottom = mHeight - getPaddingBottom();

		mPaint.setColor(mTextColor);
		mPaint.setStyle(Style.FILL);
		/**
		 * 当前设置的宽度小于字体须要的宽度。将字体改为xxx...
		 */
		if (mTextBound.width() > mWidth)
		{
			TextPaint paint = new TextPaint(mPaint);
			String msg = TextUtils.ellipsize(mTitle, paint, (float) mWidth - getPaddingLeft() - getPaddingRight(),
					TextUtils.TruncateAt.END).toString();
			canvas.drawText(msg, getPaddingLeft(), mHeight - getPaddingBottom(), mPaint);

		} else
		{
			//正常情况，将字体居中
			canvas.drawText(mTitle, mWidth / 2 - mTextBound.width() * 1.0f / 2, mHeight - getPaddingBottom(), mPaint);
		}

		//取消使用掉的快
		rect.bottom -= mTextBound.height();

		if (mImageScale == IMAGE_SCALE_FITXY)
		{
			canvas.drawBitmap(mImage, null, rect, mPaint);
		} else
		{
			//计算居中的矩形范围
			rect.left = mWidth / 2 - mImage.getWidth() / 2;
			rect.right = mWidth / 2 + mImage.getWidth() / 2;
			rect.top = (mHeight - mTextBound.height()) / 2 - mImage.getHeight() / 2;
			rect.bottom = (mHeight - mTextBound.height()) / 2 + mImage.getHeight() / 2;

			canvas.drawBitmap(mImage, null, rect, mPaint);
		}

	}

代码，结合凝视和第一篇View的使用，应该能够看懂，不明确的留言。以下我们引入我们的自己定义View:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:zhy="http://schemas.android.com/apk/res/com.zhy.customview02"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <com.zhy.customview02.view.CustomImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="10dp"
        android:padding="10dp"
        zhy:image="@drawable/ic_launcher"
        zhy:imageScaleType="center"
        zhy:titleText="hello andorid ! "
        zhy:titleTextColor="#ff0000"
        zhy:titleTextSize="30sp" />

    <com.zhy.customview02.view.CustomImageView
        android:layout_width="100dp"
        android:layout_height="wrap_content"
        android:layout_margin="10dp"
        android:padding="10dp"
        zhy:image="@drawable/ic_launcher"
        zhy:imageScaleType="center"
        zhy:titleText="helloworldwelcome"
        zhy:titleTextColor="#00ff00"
        zhy:titleTextSize="20sp" />

    <com.zhy.customview02.view.CustomImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="10dp"
        android:padding="10dp"
        zhy:image="@drawable/lmj"
        zhy:imageScaleType="center"
        zhy:titleText="妹子~"
        zhy:titleTextColor="#ff0000"
        zhy:titleTextSize="12sp" />

</LinearLayout>

我特意让显示出现3中情况：

1、字体的宽度大于图片，且View宽度设置为wrap_content

2、View宽度设置为精确值。字体的长度大于此宽度

3、图片的宽度大于字体。且View宽度设置为wrap_content

看看显示效果：

怎么样，对于这三种情况所展示的效果都还不错吧。

好了，就到这里，各位看官，没事留个言，顶一个呗~

源代码点击下载