Android 自己定義View (二) 進階

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轉載請標明出處：http://blog.csdn.net/lmj623565791/article/details/24300125

繼續自己定義View之旅。前面已經介紹過一個自己定義View的基礎的範例，Android 自己定義View (一)，假設你還對自己定義View不瞭解能夠去看看。今天給大家帶來一個略微複雜點的範例。

自己定義View顯示一張圖片，以下包括圖片的文本介紹，類似相片介紹什麼的，只是不重要，主要是學習自己定義View的使用方法麼。

還記得上一篇講的4個步驟麼:

1、自己定義View的屬性
2、在View的構造方法中獲得我們自己定義的屬性
[ 3、重寫onMesure ]
4、重寫onDraw

直接切入正題：

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、在構造中獲得我們的自己定義屬性：

/** * 初始化所特有自己定義類型 *  * @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);// 計算了描繪字型須要的範圍mPaint.getTextBounds(mTitle, 0, mTitle.length(), mTextBound);}

3、重寫onMeasure

@Overrideprotected void onMeasure(int widthMeasureSpec, int heightMeasureSpec){// super.onMeasure(widthMeasureSpec, heightMeasureSpec);/** * 設定寬度 */int specMode = MeasureSpec.getMode(widthMeasureSpec);int specSize = MeasureSpec.getSize(widthMeasureSpec);if (specMode == MeasureSpec.EXACTLY)// match_parent , accurate{Log.e("xxx", "EXACTLY");mWidth = specSize;} else{// 由圖片決定的寬int desireByImg = getPaddingLeft() + getPaddingRight() + mImage.getWidth();// 由字型決定的寬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");}}/*** * 設定高度 */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、重寫onDraw

@Overrideprotected void onDraw(Canvas canvas){// super.onDraw(canvas);/** * 邊框 */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);/** * 當前設定的寬度小於字型須要的寬度。將字型改為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{//正常情況，將字型置中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{//計算置中的矩形範圍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);}}

代碼，結合凝視和第一篇View的使用，應該能夠看懂，不明確的留言。以下我們引入我們的自己定義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>

我特意讓顯示出現3中情況：

1、字型的寬度大於圖片，且View寬度設定為wrap_content

2、View寬度設定為精確值。字型的長度大於此寬度

3、圖片的寬度大於字型。且View寬度設定為wrap_content

看看顯示效果：

怎麼樣，對於這三種情況所展示的效果都還不錯吧。

好了，就到這裡，各位看官，沒事留個言，頂一個唄~

原始碼點擊下載

Android 自己定義View (二) 進階