android开发之自定义组件

自定义Android组件可以帮助我们实现一些特殊需求,而且使得我们的应用变得更加灵活,今天我给大家介绍的是如何自定义一个组件,实现特殊的效果.

 

package jack.label;



import android.app.Activity;



import android.os.Bundle;



public class RoundRectLabel extends Activity {



    @Override



    public void onCreate(Bundle savedInstanceState) {



        super.onCreate(savedInstanceState);



        setContentView(R.layout.round_rect_label);



    }



}

package jack.label;



import java.util.ArrayList;



import java.util.List;



import android.content.Context;



import android.content.res.TypedArray;



import android.graphics.Canvas;



import android.graphics.Color;



import android.graphics.Paint;



import android.graphics.Path;



import android.graphics.RectF;



import android.graphics.Path.Direction;



import android.util.AttributeSet;



import android.view.View;



public class RoundRectLabelView extends View



{



private Paint mTextPaint;



private String mText;



private int mAscent = 0;



private List<String> textList = new ArrayList<String>();



private int mTextHeight;



private int width = 0;



private int height = 0;



final int border_width = 5;



private String mTitle;



public RoundRectLabelView(Context context)



{



super(context);



initLabelView();



}



public RoundRectLabelView(Context context, AttributeSet attrs)



{



super(context, attrs);



initLabelView();



TypedArray Attributes = context.obtainStyledAttributes(attrs,



R.styleable.LabelView);



CharSequence s = Attributes.getString(R.styleable.LabelView_text);



if (s != null)



{



setText(s.toString());



}



CharSequence title=Attributes.getString(R.styleable.LabelView_titleText);



if (title!=null)



{



    setTitle(title.toString());



}



setTextColor(Attributes.getColor(R.styleable.LabelView_textColor,



0xFF000000));



int textSize = Attributes.getDimensionPixelOffset(



R.styleable.LabelView_textSize, 0);



if (textSize > 0)



{



setTextSize(textSize);



}



Attributes.recycle();



}



public void setText(String text)



{



mText = text;



requestLayout();



invalidate();



}



public void setTextSize(int size)



{



mTextPaint.setTextSize(size);



requestLayout();



invalidate();



}



private final void initLabelView()



{



mTextPaint = new Paint();



mTextPaint.setAntiAlias(true);



mTextPaint.setTextSize(16);



mTextPaint.setColor(0xFF000000);



setPadding(3, 3, 3, 3);



mTitle="";



}



public void setTitle(String title)



{



mTitle = title;



requestLayout();



invalidate();



}



public void setTextColor(int color)



{



mTextPaint.setColor(color);



invalidate();



}



protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)



{



int strCount = 0;



textList.removeAll(textList);



StringBuilder strBuilder = new StringBuilder();



strBuilder.append(mText);



int specMode = MeasureSpec.getMode(widthMeasureSpec);



mTextHeight = Math.abs(mTextPaint.getFontMetricsInt().top)



+ Math.abs(mTextPaint.getFontMetricsInt().bottom)



+ mTextPaint.getFontMetricsInt().leading;



mAscent = (int) (-mTextPaint.ascent() + mTextPaint.descent());



if (specMode == MeasureSpec.EXACTLY)



{



width = MeasureSpec.getSize(widthMeasureSpec);



do



{



int count = mTextPaint.breakText(strBuilder.substring(0), true,



width - 2 * border_width, null);



String str = new String(strBuilder.substring(0, count));



textList.add(str);



strBuilder.delete(0, count);



strCount += count;



} while (strCount < mText.length());



}



height = textList.size() * mTextHeight + mTextHeight



+ mTextPaint.getFontMetricsInt().leading;



setMeasuredDimension(width, height + 20);



}



protected void onDraw(Canvas canvas)



{



final int radius_x = 10;



final int radius_y = 10;



final int space = 2;



final int offset_height = 20;



final int offset_one = 30;



final int offset_two = offset_one + 10;



final int offset_three = offset_two + 10;



int text_y = 0;



int text_x = 0;



Path path = new Path();



RectF rect = new RectF(space, space, width - space, height);



path.addRoundRect(rect, radius_x, radius_y, Direction.CW);



path.moveTo(space + offset_one, height);



path.lineTo(space + offset_two, height + offset_height);



path.lineTo(space + offset_three, height);



path.close();



mTextPaint.setColor(Color.WHITE);



mTextPaint.setStyle(Paint.Style.FILL);



canvas.drawPath(path, mTextPaint);



mTextPaint.setColor(Color.BLUE);



canvas.drawText(mTitle, text_x + 5, text_y + mAscent, mTextPaint);



mTextPaint.setColor(Color.GREEN);



canvas.drawLine(space, mTextHeight + 1, width - space, mTextHeight + 1,



mTextPaint);



mTextPaint.setColor(Color.DKGRAY);



for (int i = 0; i < textList.size(); i++)



{



canvas.drawText(textList.get(i), text_x + 5, text_y + mAscent + i



* mTextHeight + mTextHeight, mTextPaint);



}



}



}

<!--round_rect_label.xml-->



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



<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"



xmlns:app="http://schemas.android.com/apk/res/jack.label"



android:orientation="vertical" android:layout_width="fill_parent"



android:layout_height="wrap_content">



<jack.label.RoundRectLabelView



android:background="#7f00" android:layout_width="fill_parent"



android:layout_height="wrap_content" app:titleText="我是标题,红色背景的"



app:text="文本测试" />



<jack.label.RoundRectLabelView



android:background="@drawable/blue" android:layout_width="fill_parent"



android:layout_height="wrap_content" app:titleText="我是标题,蓝色背景的"



app:text="测试文本中英文混合,自动换行,测试文本中英文混合,自动换行,测试文本中英文混合,自动换行,测试文本中英文混合,自动换行,测试文本中英文混合,自动换行,"



app:textSize="20dp" />



<jack.label.RoundRectLabelView



android:background="@drawable/green" android:layout_width="fill_parent"



android:layout_height="wrap_content"



app:titleText="我是标题,绿色背景的"



app:text="大字体测试"



app:textSize="30dp"



app:textColor="#ffffffff" />



</LinearLayout>



<!--attrs.xml-->



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



<resources>



<declare-styleable name="TogglePrefAttrs">



<attr name="android:preferenceLayoutChild" />



</declare-styleable>



<declare-styleable name="Gallery1">



<attr name="android:galleryItemBackground" />



</declare-styleable>



<declare-styleable name="LabelView">



<attr name="text" format="string" />



<attr name="titleText" format ="string"/>



<attr name="textColor" format="color" />



<attr name="textSize" format="dimension" />



</declare-styleable>



</resources>



<!--colors.xml-->



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



<resources>



<drawable name="red">#7f00</drawable>



<drawable name="blue">#770000ff</drawable>



<drawable name="green">#7700ff00</drawable>



<drawable name="yellow">#77ffff00</drawable>



</resources>



<!--strings.xml-->



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



<resources>



<string name="hello">Hello World, RoundRectLabel!</string>



<string name="app_name">RoundRectLabel</string>



</resources>



<!--AndroidManifest.xml-->



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



<manifest xmlns:android="http://schemas.android.com/apk/res/android"



package="jack.label"



android:versionCode="1"



android:versionName="1.0">



<application android:icon="@drawable/icon" android:label="@string/app_name">



<activity android:name=".RoundRectLabel"



android:label="@string/app_name">



<intent-filter>



<action android:name="android.intent.action.MAIN" />



<category android:name="android.intent.category.LAUNCHER" />



</intent-filter>



</activity>



</application>



</manifest>