Question

如果URL存在，我怎样才能获得新图像。

这是我的活动代码：

package com.ddd.funnic.TouchView;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
import android.util.AttributeSet;
import android.widget.ImageView.ScaleType;
import android.widget.ProgressBar;
import android.widget.RelativeLayout;

import java.io.InputStream;
import java.net.URL;
import java.net.URLConnection;

import com.ddd.R;
import com.ddd.TouchView.InputStreamWrapper.InputStreamProgressListener;


public class UrlTouchImageView extends RelativeLayout {
    protected ProgressBar mProgressBar;
    protected TouchImageView mImageView = null;

    protected Context mContext;


    public UrlTouchImageView(Context ctx)
    {
        super(ctx);
        mContext = ctx;
        init();

    }
    public UrlTouchImageView(Context ctx, AttributeSet attrs)
    {
        super(ctx, attrs);
        mContext = ctx;
        init();
    }
    public TouchImageView getImageView() { return mImageView; }

    @SuppressWarnings("deprecation")
    protected void init() {
        mImageView = new TouchImageView(mContext);
        LayoutParams params = new LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT);
        mImageView.setLayoutParams(params);
        this.addView(mImageView);
        mImageView.setVisibility(GONE);

        mProgressBar = new ProgressBar(mContext, null, android.R.attr.progressBarStyleHorizontal);
        params = new LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT);
        params.addRule(RelativeLayout.CENTER_VERTICAL);
        params.setMargins(30, 0, 30, 0);
        mProgressBar.setLayoutParams(params);
        mProgressBar.setIndeterminate(false);
        mProgressBar.setMax(100);
        this.addView(mProgressBar);
    }

    public void setUrl(String imageUrl)
    {
        new ImageLoadTask().execute(imageUrl);
    }
    //No caching load
    public class ImageLoadTask extends AsyncTask<String, Integer, Bitmap>
    {
        @Override
        protected Bitmap doInBackground(String... strings) {
            String url = strings[0];
            Bitmap bm = null;
            try {
                URL aURL = new URL(url);
                URLConnection conn = aURL.openConnection();
                conn.connect();
                InputStream is = conn.getInputStream();
                int totalLen = conn.getContentLength();
                InputStreamWrapper bis = new InputStreamWrapper(is, 8192, totalLen);
                bis.setProgressListener(new InputStreamProgressListener()
                {                   
                    @Override
                    public void onProgress(float progressValue, long bytesLoaded,
                            long bytesTotal)
                    {
                        publishProgress((int)(progressValue * 100));
                    }
                });
                bm = BitmapFactory.decodeStream(bis);
                bis.close();
                is.close();
            } catch (Exception e) {
                e.printStackTrace();
            }
            return bm;
        }
        @Override
        protected void onPostExecute (Bitmap bitmap) {
            if (bitmap == null)  
            {

                mImageView.setScaleType(ScaleType.CENTER);
                bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.no_photo);
                mImageView.setImageBitmap(bitmap);

            }


            if(bitmap != null)
            {

                mImageView.setScaleType(ScaleType.MATRIX);
                mImageView.setImageBitmap(bitmap);

            }

            mImageView.setVisibility(VISIBLE);
            mProgressBar.setVisibility(GONE);

            }

        @Override
        protected void onProgressUpdate(Integer... values)
        {
            mProgressBar.setProgress(values[0]);
        }



        }

        }

如果 Bitmap == null ，我想要一个新的Url来加载另一个图片。

请帮助我，这非常重要。

Answer 1

在ImageLoadTask中，您打开URLConnection。如果该连接不存在，将抛出异常并执行catch子句中的代码。您可以return catch子句中的public class ImageLoadTask extends AsyncTask<String, Integer, Bitmap> { @Override protected Bitmap doInBackground(String... strings) { String url = strings[0]; Bitmap bm = null; try { ... ... } catch (Exception e) { e.printStackTrace(); // add this line bm = BitmapFactory.decodeResource(getResources(), R.drawable.no_photo); // <--------------- } return bm; } ... ... }默认位图。

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跳过错误url android

1 个答案: