Android读取并浏览SD Card图片示例

package mike.android.sdcard; import java.io.File; import java.util.ArrayList; import java.util.List; import mike.android.R; import android.app.Activity; import android.app.ProgressDialog; import android.content.DialogInterface; import android.content.DialogInterface.OnDismissListener; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.os.Bundle; import android.os.Environment; import android.view.View; import android.view.View.OnClickListener; import android.widget.Button; import android.widget.ImageView; import android.widget.TextView; import android.widget.Toast; public class BrowseSDCardImagesActivity extends Activity { private ImageView imageView; private Button previousButton; private Button nextButton; private TextView titleTextView; public ProgressDialog progressDialog = null; private int imageIndex = -1; private static final CharSequence dialogTitle = "载入图片中"; private static final CharSequence dialogBody = "载入图片中"; private List<String> imagePaths; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); final List<String> imagePaths = getSDCard(); if (imagePaths.size() > 0) { Toast.makeText(this, "有" + imagePaths.size() + "张相片在SD卡根目录", Toast.LENGTH_LONG).show(); imageView = (ImageView) findViewById(R.id.imageView1); titleTextView = (TextView) findViewById(R.id.titleTextView); previousButton = (Button) findViewById(R.id.previousButton); nextButton = (Button) findViewById(R.id.nextButton); nextButton.setOnClickListener(new OnClickListener() { @Override public void onClick(View view) { switchToNextImage(); } }); previousButton.setOnClickListener(new OnClickListener() { @Override public void onClick(View view) { switchToPreviousImage(); } }); } else { Toast.makeText(this, "无相片在SD卡根目录", Toast.LENGTH_LONG).show(); } } public String getSDPath() { File sdDir = null; boolean sdCardExist = Environment.getExternalStorageState().equals(android.os.Environment.MEDIA_MOUNTED); // 判断sd卡是否存在 if (sdCardExist) { sdDir = Environment.getExternalStorageDirectory(); } return sdDir != null ? sdDir.toString() : "没发现SDCard"; } private List<String> getSDCard() { imagePaths = new ArrayList<String>(); try { File file = new File(getSDPath()); File[] files = file.listFiles(); for (File theFile : files) { if (matchImageFile(theFile.getPath())) { imagePaths.add(theFile.getPath()); } } } catch (Exception e) { return imagePaths; } return imagePaths; } private boolean matchImageFile(String fileName) { String extension = fileName.substring(fileName.lastIndexOf(".") + 1, fileName.length()).toLowerCase(); if (extension.equals("jpg") || extension.equals("png") || extension.equals("gif") || extension.equals("jpeg") || extension.equals("bmp")) { return true; } return false; } private String parsePathForImageName(String path) { int lastSeparatorIndex = path.lastIndexOf("/"); return path.substring(lastSeparatorIndex + 1, path.length()); } private void switchToNextImage() { next(); showProgressDialog(); } private void switchToPreviousImage() { previous(); showProgressDialog(); } private void showProgressDialog() { progressDialog = ProgressDialog.show(BrowseSDCardImagesActivity.this, dialogTitle, dialogBody, true); ProcessThread processThread = new ProcessThread(); progressDialog.setOnDismissListener(processThread); progressDialog.show(); processThread.start(); } private void next() { if (imageIndex < imagePaths.size() - 1) { imageIndex += 1; } else { imageIndex = 0; } } private void previous() { if (imageIndex > 1) { imageIndex -= 1; } else { imageIndex = imagePaths.size() - 1; } } private void drawImage() { String path = imagePaths.get(imageIndex); titleTextView.setText("第" + (imageIndex + 1) + "张相片:" + parsePathForImageName(path)); Bitmap firstBitmap = BitmapFactory.decodeFile(path); imageView.setImageBitmap(firstBitmap); } private class ProcessThread extends Thread implements OnDismissListener { public void run() { try { sleep(200); } catch (InterruptedException e) { } finally { progressDialog.dismiss(); } } @Override public void onDismiss(DialogInterface arg0) { drawImage(); } } }