Picasso高逼格使用技巧

来源：互联网发布：淘宝上的shockabsorber 编辑：程序博客网时间：2024/06/06 19:42

此文主要实现两方面功能：

1 设置Picasso的缓存路径---默认Picasso的缓存都是在内置存储的cache路径下，如果下载较大图片则会导致下载不成功，但是系统也没有报错坑。。。

2 Picasso下载图片时，自带下载进度提示，当下载完成时显示图片，如下图所示：

完整代码在这：http://download.csdn.net/detail/zxm317122667/9566123

接下来说下实现步骤：

1 导入依赖库

众所周知，Picasso内部网络请求使用的是OkHttp，而Picasso和OkHttp都是一家叫做Square的公司的亲儿子。因此我们要重新设置Picasso网络请求实现，需要将这两个包都添加到依赖中，在build.gradle中添加如下代码：

repositories {        maven { url "https://oss.sonatype.org/content/repositories/snapshots" }        maven {            url "http://maven.bughd.com/public"        }    }compile "com.squareup.picasso:picasso:2.5.3-SNAPSHOT"compile 'com.squareup.okhttp3:okhttp:3.3.1'

以上代码中，注意 Picasso的依赖一定要是comple "com.squareup.picasso:picasso:2.5.3-SNAPSHOT"

2 获取Picasso

重写OkHttp的Client类，并将重写的Client传递给自定义的Picasso，代码如下：

package material.danny_jiang.com.picassosenior.utils;import android.content.Context;import android.support.annotation.IntRange;import android.support.annotation.WorkerThread;import com.squareup.picasso.OkHttp3Downloader;import com.squareup.picasso.Picasso;import java.io.File;import java.io.IOException;import material.danny_jiang.com.picassosenior.MyApplication;import okhttp3.Cache;import okhttp3.Interceptor;import okhttp3.MediaType;import okhttp3.OkHttpClient;import okhttp3.Response;import okhttp3.ResponseBody;import okio.Buffer;import okio.BufferedSource;import okio.ForwardingSource;import okio.Okio;import okio.Source;/** * Created by axing on 16/7/2. */public class SquareUtils {    static private OkHttpClient client;    static public synchronized OkHttpClient getClient() {        if (client == null) {            final File cacheDir = MyApplication.getInstance().getExternalCacheDir();            client = new OkHttpClient.Builder()                    //Interceptor -> cache -> NetworkInterceptor                    //.addNetworkInterceptor(getLogger())                    .cache(new Cache(new File(cacheDir, "okhttp"), 60 * 1024 * 1024))                    //.dispatcher(getDispatcher())                    //.dns(HTTP_DNS)                    .build();        }        return client;    }    /**     * Not singleton     */    private static OkHttpClient getProgressBarClient(final ProgressListener listener) {        return getClient().newBuilder().addNetworkInterceptor(new Interceptor() {            @Override            public Response intercept(Chain chain) throws IOException {                Response originalResponse = chain.proceed(chain.request());                return originalResponse.newBuilder()                        .body(new ProgressResponseBody(originalResponse.body(), listener))                        .build();            }        }).build();    }    /**     * Download Big Image only, Not singleton but shared cache     */    static public Picasso getPicasso(Context context, ProgressListener listener) {        OkHttpClient client = getProgressBarClient(listener);        OkHttp3Downloader downloader = new OkHttp3Downloader(client);        return new Picasso.Builder(context).downloader(downloader)                .memoryCache(com.squareup.picasso.Cache.NONE)                .build();    }    public interface ProgressListener {        @WorkerThread        void update(@IntRange(from = 0, to = 100) int percent);    }    private static class ProgressResponseBody extends ResponseBody {        private final ResponseBody responseBody;        private final ProgressListener progressListener;        private BufferedSource bufferedSource;        public ProgressResponseBody(ResponseBody responseBody, ProgressListener progressListener) {            this.responseBody = responseBody;            this.progressListener = progressListener;        }        @Override        public MediaType contentType() {            return responseBody.contentType();        }        @Override        public long contentLength() {            return responseBody.contentLength();        }        @Override        public BufferedSource source() {            if (bufferedSource == null) {                bufferedSource = Okio.buffer(source(responseBody.source()));            }            return bufferedSource;        }        private Source source(Source source) {            return new ForwardingSource(source) {                long totalBytesRead = 0L;                @Override                public long read(Buffer sink, long byteCount) throws IOException {                    long bytesRead = super.read(sink, byteCount);                    // read() returns the number of bytes read, or -1 if this source is exhausted.                    totalBytesRead += bytesRead != -1 ? bytesRead : 0;                    if (progressListener != null) {                        progressListener.update(                                ((int) ((100 * totalBytesRead) / responseBody.contentLength())));                    }                    return bytesRead;                }            };        }    }}

3 自定义ImageView，实现饼状图的绘制

package material.danny_jiang.com.picassosenior.view;import android.content.Context;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.graphics.RectF;import android.support.annotation.IntRange;import android.support.v4.view.ViewCompat;import android.util.AttributeSet;import android.widget.ImageView;/** * Created by axing on 3/7/16. * Image with Pie Progress * learned from com.kaopiz.kprogresshud's PieView */public class PieImageView extends ImageView {  private final int MAX_PROGRESS = 100;  private Paint mArcPaint;  private RectF mBound;  private Paint mCirclePaint;  private int mProgress = 0;  public PieImageView(Context context) {    this(context, null, 0);  }  public PieImageView(Context context, AttributeSet attrs) {    this(context, attrs, 0);  }  public PieImageView(Context context, AttributeSet attrs, int defStyleAttr) {    super(context, attrs, defStyleAttr);    init();  }  public void setProgress(@IntRange(from = 0, to = MAX_PROGRESS) int mProgress) {    this.mProgress = mProgress;    ViewCompat.postInvalidateOnAnimation(this);  }  private void init() {    mArcPaint = new Paint(Paint.ANTI_ALIAS_FLAG);    mArcPaint.setStyle(Paint.Style.FILL_AND_STROKE);    mArcPaint.setStrokeWidth(dpToPixel(0.1f, getContext()));    //mArcPaint.setColor(Color.argb(120, 0xff, 0xff, 0xff));    mArcPaint.setColor(Color.RED);    mCirclePaint = new Paint(Paint.ANTI_ALIAS_FLAG);    mCirclePaint.setStyle(Paint.Style.STROKE);    mCirclePaint.setStrokeWidth(dpToPixel(2, getContext()));    mCirclePaint.setColor(Color.argb(120, 0xff, 0xff, 0xff));    mBound = new RectF();  }  @Override protected void onSizeChanged(int w, int h, int oldw, int oldh) {    super.onSizeChanged(w, h, oldw, oldh);    int min = Math.min(w, h);    int max = w + h - min;    int r = min / 5;    //set up a square in the imageView    mBound.set(max / 2 - r, min / 2 - r, max / 2 + r, min / 2 + r);  }  @Override protected void onDraw(Canvas canvas) {    super.onDraw(canvas);    if (mProgress != MAX_PROGRESS && mProgress != 0) {      float mAngle = mProgress * 360f / MAX_PROGRESS;      canvas.drawArc(mBound, 270, mAngle, true, mArcPaint);      canvas.drawCircle(mBound.centerX(), mBound.centerY(), mBound.height() / 2, mCirclePaint);    }  }    private float scale = 0;  private int dpToPixel(float dp, Context context) {    if (scale == 0) {      scale = context.getResources().getDisplayMetrics().density;    }    return (int) (dp * scale);  }}

打完收功！

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