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>