UI控件之显示图像控件ImageView（下）

(一）绘制最简单的圆形ImageView



RoundedImageView

CircleImageView

运行效果：



实现代码：

自定义ImageView代码：

package com.example.android_drawable_xml;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.PaintFlagsDrawFilter;
import android.graphics.Path;
import android.graphics.Rect;
import android.graphics.Region;
import android.util.AttributeSet;
import android.widget.ImageView;

public class RoundImageView extends ImageView {

private Bitmap mBitmap;
private Rect mRect = new Rect();
private PaintFlagsDrawFilter pdf=new PaintFlagsDrawFilter(0, Paint.ANTI_ALIAS_FLAG);
private Paint mPaint = new Paint();
private Path mPath =  new Path();

public RoundImageView(Context context, AttributeSet attrs) {
super(context, attrs);

}

//传入一个Bitmap对象
public void setmBitmap(Bitmap bitmap) {
this.mBitmap = bitmap;
}

private void init(){
mPaint.setStyle(Paint.Style.STROKE);
mPaint.setFlags(Paint.ANTI_ALIAS_FLAG);
mPaint.setAntiAlias(true);//抗锯齿
}

@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
if (mBitmap == null) {
return;

}
mRect.set(0,0,getWidth(),getHeight());
canvas.save();
canvas.setDrawFilter(pdf);
mPath.addCircle(getWidth() / 2 , getWidth() / 2 , getHeight() / 2 , Path.Direction.CCW);
canvas.clipPath(mPath,Region.Op.REPLACE);
canvas.drawBitmap(mBitmap, null, mRect, mPaint);
canvas.restore();
}
}

MainActivity.java

package com.example.android_drawable_xml;

import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;

public class MainActivity extends Activity {

private RoundImageView img_roundImageView;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main2);
RoundImageView img_roundImageView = (RoundImageView) findViewById(R.id.img_round);
Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.bulunou);

img_roundImageView.setmBitmap(bitmap);
}

}

activity_main.xml文件

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context="com.example.android_drawable_xml.MainActivity" >

<com.example.android_drawable_xml.RoundImageView
android:id="@+id/img_round"
android:layout_width="200dp"
android:layout_height="200dp"
android:layout_margin="5px"
android:layout_gravity="center"/>

</LinearLayout>

（二）ImageView实现图片裁剪和显示的功能

网上一张图：



这个是QQ的剪切图来设置头像的，其实就是一个ImageView的剪切与显示；

运行结果：



做的比较粗糙~~~你可以在此基础上精雕细琢下~

实现代码：

package com.example.android_imageview;

import android.app.Activity;
import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.net.Uri;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ImageView;

public class CutImageView extends Activity implements OnClickListener{

private Button selectImageBtn;
private Button cutImageBtn;
private ImageView imageView;
// 声明两个静态的整型变量，主要是用于意图的返回的标志
private static final int IMAGE_SELECT = 1;// 选择图片
private static final int IMAGE_CUT = 2;// 裁剪图片

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.cut_imageview);
selectImageBtn = (Button) this.findViewById(R.id.selectImgBtn);
cutImageBtn = (Button) this.findViewById(R.id.cutImageBtn);
imageView = (ImageView) this.findViewById(R.id.imageview3);
selectImageBtn.setOnClickListener(this);
cutImageBtn.setOnClickListener(this);
// imageView.setImageBitmap(bm);
}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
// TODO Auto-generated method stub
super.onActivityResult(requestCode, resultCode, data);
if (resultCode == RESULT_OK) {
// 处理图片按照手机的屏幕大小显示
if (requestCode == IMAGE_SELECT) {
Uri uri = data.getData();// 获得图片的路径
int dw = getWindowManager().getDefaultDisplay().getWidth();// 获得屏幕的宽度
int dh = getWindowManager().getDefaultDisplay().getHeight() / 2;
try {
// 实现对图片的裁剪的类,是一个匿名内部类
BitmapFactory.Options factory = new BitmapFactory.Options();
factory.inJustDecodeBounds = true;// 如果设置为true，允许查询图片不是按照像素分配给内存
Bitmap bmp = BitmapFactory.decodeStream(
getContentResolver().openInputStream(uri), null,
factory);
// 对图片的宽度和高度对应手机的屏幕进行匹配

int hRatio = (int) Math
.ceil(factory.outHeight / (float) dh);
// 如果大于1 表示图片的高度大于手机屏幕的高度
int wRatio = (int) Math.ceil(factory.outWidth / (float) dw);
// 如果大于1 表示图片的宽度大于手机屏幕的宽度
// 缩放到1/radio的尺寸和1/radio^2像素
if (hRatio > 1 || wRatio > 1) {
if (hRatio > wRatio) {
factory.inSampleSize = hRatio;
} else {
factory.inSampleSize = wRatio;
}
}
// 对
factory.inJustDecodeBounds = false;
// 使用BitmapFactory对图片进行适屏的操作，
bmp = BitmapFactory.decodeStream(getContentResolver()
.openInputStream(uri), null, factory);
imageView.setImageBitmap(bmp);
} catch (Exception e) {
// TODO: handle exception
}
// 表示裁剪图片
} else if (requestCode == IMAGE_CUT) {
Bitmap bitmap = data.getParcelableExtra("data");
imageView.setImageBitmap(bitmap);
}
}
}

@Override
public void onClick(View v) {
// TODO Auto-generated method stub
switch (v.getId()) {
case R.id.selectImgBtn:
// 如何提取手机的图片的，并且进行选择图片的功能
Intent intent = new Intent(
Intent.ACTION_PICK,
android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);// 打开手机的图片库
startActivityForResult(intent, IMAGE_SELECT);
break;

case R.id.cutImageBtn:
Intent intent2 = getImageClipIntent();
startActivityForResult(intent2, IMAGE_CUT);
break;
}
}

private Intent getImageClipIntent() {
// TODO Auto-generated method stub
Intent intent = new Intent(Intent.ACTION_GET_CONTENT, null);
// 实现对图片的裁剪，必须要设置图片的属性和大小
intent.setType("image/*");// 获取任意的图片类型
intent.putExtra("crop", "true");// 滑动选中图片区域
intent.putExtra("aspectX", 1);// 表示剪切框的比例1:1的效果
intent.putExtra("aspectY", 1);
intent.putExtra("outputX", 80);// 指定输出图片的大小
intent.putExtra("outputY", 80);
intent.putExtra("return-data", true);
return intent;
}
}

cut_imageview.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >

<Button android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/selectImgBtn"
android:text="选择图片"/>
<Button android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/cutImageBtn"
android:text="选择图片进行裁剪"/>
<!-- 用于显示图片的信息 -->
<ImageView android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/imageview3"/>
</LinearLayout>

（三）ImageView实现图片图片旋转

在开发中实现对图像的缩放有很多方法，最简单的方法是改变ImageView控件的大小，我们只要将

<ImageView>

标签的android:scaleType的属性值设置为fitCenter，

要是想实现图像的旋转可以使用android.graphics.Matirx类的setRotate来实现.

运行效果如下：



实现代码：

public class ImageViewRotateText extends Activity  implements OnSeekBarChangeListener{

private int minWidth=80;
private ImageView imageView;
private TextView textView1 ,textView2;
private Matrix matrix = new Matrix();

@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.rotate_imageview);
imageView = (ImageView) this.findViewById(R.id.imageview5);
SeekBar seekBar1 = (SeekBar) this.findViewById(R.id.seekbar1);
SeekBar seekBar2 = (SeekBar) this.findViewById(R.id.seekbar2);
textView1 = (TextView) this.findViewById(R.id.textview1);
textView2 = (TextView) this.findViewById(R.id.textview2);
seekBar1.setOnSeekBarChangeListener(this);
seekBar2.setOnSeekBarChangeListener(this);

//
DisplayMetrics dm = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(dm);
seekBar1.setMax(dm.widthPixels - minWidth);
}

@Override
public void onProgressChanged(SeekBar seekBar, int progress,
boolean fromUser) {
// TODO Auto-generated method stub
if (seekBar.getId() == R.id.seekbar1) {
int newWidth = progress + minWidth;
int newHeight = (int)(newWidth * 3 / 4);//按照原图进行缩放的功能
imageView.setLayoutParams( new LinearLayout.LayoutParams(newWidth , newHeight));
textView1.setText("图像宽度:  "+newWidth+"图像高度：   "+newHeight);

}else if (seekBar.getId() == R.id.seekbar2) {
Bitmap bitmap = ((BitmapDrawable)(getResources()
.getDrawable(R.drawable.xingkong))).getBitmap();
matrix.setRotate(progress);//设置翻转的角度
bitmap = Bitmap.createBitmap(bitmap ,0,0,bitmap.getWidth(),
bitmap.getHeight() , matrix, true);
imageView.setImageBitmap(bitmap);
textView2.setText(progress+"度");

}

}

@Override
public void onStartTrackingTouch(SeekBar seekBar) {
// TODO Auto-generated method stub

}

@Override
public void onStopTrackingTouch(SeekBar seekBar) {
// TODO Auto-generated method stub

}

}

xml文件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >

<Button android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/selectImgBtn"
android:text="选择图片"/>
<Button android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/cutImageBtn"
android:text="选择图片进行裁剪"/>
<!-- 用于显示图片的信息 -->
<ImageView android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/imageview3"/>
</LinearLayout>

(四）使用ImageView获取网络图片

运行效果：



实现代码：

xml文件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="fill_parent"
android:layout_height="fill_parent">
<ImageView android:id="@+id/imageview" android:layout_width="wrap_content"
android:layout_height="wrap_content" />

<Button android:id="@+id/button" android:layout_width="fill_parent"
android:layout_height="wrap_content" android:text="下载网络图片" />
</LinearLayout>

main.java

public class Main extends Activity {

private Button button;
private ImageView imageView;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
button = (Button) this.findViewById(R.id.button);
imageView = (ImageView) this.findViewById(R.id.imageview);
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
// try {
// InputStream inputStream = HttpUtils
// .getImageViewInputStream();
// Bitmap bitmap = BitmapFactory.decodeStream(inputStream);
// imageView.setImageBitmap(bitmap);
// } catch (IOException e) {
// // TODO: handle exception
// }
byte[] data = HttpUtils.getImageViewArray();
Bitmap bitmap = BitmapFactory.decodeByteArray(data, 0,
data.length);
imageView.setImageBitmap(bitmap);

}
});
}
}

使用Http协议获取网络图片

HttpUtils.java

public class HttpUtils {

private final static String URL_PATH = "http://img.my.csdn.net/uploads/201202/8/0_13287131646nNZ.gif";// 访问网路图片的路径

public HttpUtils() {
// TODO Auto-generated constructor stub
}

/**
* 从网络中获取图片信息，以流的形式返回
*
* @return
*/
public static InputStream getImageViewInputStream() throws IOException {
InputStream inputStream = null;

URL url = new URL(URL_PATH);
if (url != null) {
HttpURLConnection httpURLConnection = (HttpURLConnection) url
.openConnection();
httpURLConnection.setConnectTimeout(3000);// 设置连接超时的时间
httpURLConnection.setRequestMethod("GET");
httpURLConnection.setDoInput(true);
int response_code = httpURLConnection.getResponseCode();
if (response_code == 200) {
inputStream = httpURLConnection.getInputStream();
}
}
return inputStream;
}

/**
* 从网络中获取图片信息，以字节数组的形式返回
*
* @return
*/
public static byte[] getImageViewArray() {
byte[] data = null;
InputStream inputStream = null;
// 不需要关闭的输出流，直接写入到内存中
ByteArrayOutputStream outputStream = new ByteArrayOutputStream();

try {
URL url = new URL(URL_PATH);
if (url != null) {
HttpURLConnection httpURLConnection = (HttpURLConnection) url
.openConnection();
httpURLConnection.setConnectTimeout(3000);// 设置连接超时的时间
httpURLConnection.setRequestMethod("GET");// 请求方法
httpURLConnection.setDoInput(true);// 打开输入流
int response_code = httpURLConnection.getResponseCode();
int len = 0;
byte[] b_data = new byte[1024];

if (response_code == 200) {
inputStream = httpURLConnection.getInputStream();
while ((len = inputStream.read(b_data)) != -1) {
outputStream.write(b_data, 0, len);
}
data = outputStream.toByteArray();
}
}
} catch (Exception e) {
// TODO: handle exception
} finally {
if (inputStream != null) {
try {
inputStream.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
return data;
}
}

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