轉載請標明出處:http://blog.csdn.NET/lmj623565791/article/details/24300125
繼續自定義View之旅,前面已經介紹過一個自定義View的基礎的例子,Android 自定義View (一),如果你還對自定義View不瞭解可以去看看。今天給大家帶來一個稍微複雜點的例子。
自定義View顯示一張圖片,下面包含圖片的文本介紹,類似相片介紹什麼的,不過不重要,主要是學習自定義View的用法麼。
還記得上一篇講的4個步驟麼:
1、自定義View的屬性
2、在View的構造方法中獲得我們自定義的屬性
[ 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定義屬性:
- /**
- * 初始化所特有自定義類型
- *
- * @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);
- // 計算了描繪字體需要的範圍
- mPaint.getTextBounds(mTitle, 0, mTitle.length(), mTextBound);
- }
3、重寫onMeasure
- @Override
- protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
- {
- // super.onMeasure(widthMeasureSpec, heightMeasureSpec);
- /**
- * 設置寬度
- */
- 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();
- // 由字體決定的寬
- 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、重寫onDraw
- @Override
- protected 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);
- /**
- * 當前設置的寬度小於字體需要的寬度,將字體改爲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,將字體居中
- 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
- {
- //計算居中的矩形範圍
- 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,結合註釋和第一篇View的使用,應該可以看懂,不明白的留言。下面我們引入我們的自定義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、字體的寬度大於圖片,且View寬度設置爲wrap_content
2、View寬度設置爲精確值,字體的長度大於此寬度
3、圖片的寬度大於字體,且View寬度設置爲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,就到這裏,各位看官,沒事留個言,頂一個唄~