【Android】安卓中常用的图片加载方法

一、通过相机选图片：

布局文件:

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

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

android:layout_width="fill_parent"

android:layout_height="fill_parent"

android:orientation="vertical" android:gravity="center_horizontal">

<Button

android:id="@+id/button"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="使用系统照相机拍照" android:onClick="click"/>
<ImageView

android:id="@+id/imageView"

android:layout_width="wrap_content"

android:layout_height="wrap_content" />
</LinearLayout>

代码：

package uk.ac.essex.camerademo1;

import java.io.File;
import android.app.Activity;

import android.content.Intent;

import android.graphics.Bitmap;

import android.graphics.BitmapFactory;

import android.graphics.BitmapFactory.Options;

import android.net.Uri;

import android.os.Bundle;

import android.os.Environment;

import android.provider.MediaStore;

import android.view.Display;

import android.view.View;

import android.widget.ImageView;
public class Camerademo1Activity extends Activity {

    private static final int CAPTURE_PIC = 0;
private ImageView imageView;
private int width;

    private int height;

    private String imageFilePath;

    private Uri imageFileUri;
/** Called when the activity is first created. */

    @Override

    public void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.main);

        imageView = (ImageView) findViewById(R.id.imageView);

        init();

    }
private void init() {

        Display display = getWindowManager().getDefaultDisplay();

        width = display.getWidth();

        height = display.getHeight();
imageFilePath = Environment.getExternalStorageState().equals(

                Environment.MEDIA_MOUNTED) ? Environment

                .getExternalStorageDirectory() + "/1.jpg" : null;

        imageFileUri = Uri.fromFile(new File(imageFilePath));

    }
public void click(View view) {

        Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);// 相机捕捉图片的意图

        intent.putExtra(MediaStore.EXTRA_OUTPUT, imageFileUri);// 指定系统相机拍照保存在imageFileUri所指的位置

        startActivityForResult(intent, CAPTURE_PIC);// 启动系统相机,等待返回

    }
@Override

    protected void onActivityResult(int requestCode, int resultCode, Intent data) {

        if (resultCode == RESULT_OK && requestCode == CAPTURE_PIC) {

            Options options = new Options();

            options.inJustDecodeBounds = true;// 设置解码只是为了获取图片的width和height值,而不是真正获取图片

            Bitmap bitmap = BitmapFactory.decodeFile(imageFilePath, options);// 解码后可以options.outWidth和options.outHeight来获取图片的尺寸
int widthRatio = (int) Math.ceil(options.outWidth / width);// 获取宽度的压缩比率

            int heightRatio = (int) Math.ceil(options.outHeight / height);// 获取高度的压缩比率
if (widthRatio > 1 || heightRatio > 1) {// 只要其中一个的比率大于1,说明需要压缩

                if (widthRatio >= heightRatio) {// 取options.inSampleSize为宽高比率中的最大值

                    options.inSampleSize = widthRatio;

                } else {

                    options.inSampleSize = heightRatio;

                }

            }
options.inJustDecodeBounds = false;// 设置为真正的解码图片

            bitmap = BitmapFactory.decodeFile(imageFilePath, options);// 解码图片
imageView.setImageBitmap(bitmap);

        }

        super.onActivityResult(requestCode, resultCode, data);

    }
}

二、通过图库选图片：

public void Camera() {

Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);// 相机捕捉图片的意图

intent.putExtra(MediaStore.EXTRA_OUTPUT, imageFileUri);// 指定系统相机拍照保存在imageFileUri所指的位置

startActivityForResult(intent, 1);// 启动系统相机,等待返回

}

public void OpenImage() {

Intent intent = new Intent();

intent.setType("image/*");

intent.setAction(Intent.ACTION_GET_CONTENT);

startActivityForResult(intent, 2);// 打开本地图库

}
protected void onActivityResult(int requestCode, int resultCode, Intent data) {

super.onActivityResult(requestCode, resultCode, data);

if (requestCode == 1 && resultCode == Activity.RESULT_OK) {

String sdStatus = Environment.getExternalStorageState();

if (!sdStatus.equals(Environment.MEDIA_MOUNTED)) { // 检测sd是否可用

Log.i("TestFile", "存储卡读取失败.");

return;

}

// Bundle bundle = data.getExtras();

// Bitmap bitmap = (Bitmap) bundle.get("data");//
Options options = new Options();

options.inJustDecodeBounds = true;// 设置解码只是为了获取图片的width和height值,而不是真正获取图片

Bitmap bitmap = BitmapFactory.decodeFile(imageFilePath, options);// 解码后可以options.outWidth和options.outHeight来获取图片的尺寸
int widthRatio = (int) Math.ceil(options.outWidth / width);// 获取宽度的压缩比率

int heightRatio = (int) Math.ceil(options.outHeight / height);// 获取高度的压缩比率
if (widthRatio > 1 || heightRatio > 1) {// 只要其中一个的比率大于1,说明需要压缩

if (widthRatio >= heightRatio) {// 取options.inSampleSize为宽高比率中的最大值

options.inSampleSize = widthRatio;

} else {

options.inSampleSize = heightRatio;

}

}
options.inJustDecodeBounds = false;// 设置为真正的解码图片

bitmap = BitmapFactory.decodeFile(imageFilePath, options);// 解码图片
}

if (requestCode == 2 && resultCode == RESULT_OK && null != data) {

Uri uri = data.getData();

if (!TextUtils.isEmpty(uri.getAuthority())) {

Cursor cursor = getContentResolver().query(uri,

new String[] { MediaStore.Images.Media.DATA }, null,

null, null);

if (null == cursor) {

Tools.ToastShort("打开失败，请重试！");

return;

}

cursor.moveToFirst();

String path = cursor.getString(cursor

.getColumnIndex(MediaStore.Images.Media.DATA));// 选择的本地图片的路径
BitmapFactory.Options opts = new BitmapFactory.Options();

opts.inJustDecodeBounds = true;

;// 设置解码只是为了获取图片的width和height值,而不是真正获取图片

BitmapFactory.decodeFile(path, opts);// 解码后可以options.outWidth和options.outHeight来获取图片的尺寸

opts.inSampleSize = 10;

opts.inJustDecodeBounds = false;// 设置为真正的解码图片
try {

Bitmap bmp = BitmapFactory.decodeFile(path, opts);
} catch (OutOfMemoryError err) {
}

http://www.eoeandroid.com/thread-3222-1-1.html

http://www.eoeandroid.com/forum.php?mod=viewthread&tid=6552&page=1