我可以通过对话框很好地查看图库，但是当我选择我想要的图像时，它会关闭图库并且似乎不会更新 ImageView 上的位图，或者将其存储为 actualprofilepicture.jpg 以便我可以加载它我想。
问题似乎是在调用 galleryResult() 并使用 Bitmap thumbnail = (Bitmap) data.getExtras().get("data); 时出现以下错误；
原因：java.lang.NullPointerException：尝试在 com.example.android.myapplication.personalHome 的空对象引用上调用虚拟方法“java.lang.Object android.os.BaseBundle.get(java.lang.String)” .galleryResult(personalHome.java:143) 在 com.example.android.myapplication.personalHome.onActivityResult(personalHome.java:132)
使用 Camera API，拍照并保存它绝对没有问题。
package com.example.android.myapplication;
import android.app.Activity;
import android.content.Context;
import android.content.DialogInterface;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.provider.MediaStore;
import android.content.Intent;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.util.Log;
import android.view.View;
import android.widget.ImageView;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import static android.R.attr.data;
import static android.R.attr.thumbnail;
import static android.provider.LiveFolders.INTENT;
import static android.widget.ImageView.ScaleType.FIT_CENTER;
public class personalHome extends AppCompatActivity {
private int REQUEST_CAMERA = 0, SELECT_FILE = 1;
private String userChoosenTask;
ImageView profileimage;
//Camera/Image code inspired and based from http://www.theappguruz.com/blog/android-take-photo-camera-gallery-code-sample
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.personal_home);
getFilesDir().getAbsolutePath();
View camera = findViewById(R.id.camera);
//the code here retrieves the selected profile picture if it exists and loads it
File imgFile = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES), "actualprofilepicture.jpg");
if(imgFile.exists()){
Bitmap myBitmap = BitmapFactory.decodeFile(imgFile.getAbsolutePath());
ImageView myImage = (ImageView) findViewById(R.id.profilepic1);
myImage.setImageBitmap(myBitmap);
//profile picture is now set in imageview on the page
}
camera.setOnClickListener(new View.OnClickListener(){
public void onClick(View v){
selectImage();
}
});
}
public void selectImage() {
final CharSequence[] items = { "Take Photo", "Choose from Library",
"Cancel" };
AlertDialog.Builder builder = new AlertDialog.Builder(personalHome.this);
builder.setTitle("Add Photo!");
builder.setItems(items, new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int item) {
boolean result = Utility.checkPermission(personalHome.this);
if (items[item].equals("Take Photo")) {
userChoosenTask = "Take Photo";
if(result)
cameraOpen();
} else if (items[item].equals("Choose from Library")) {
userChoosenTask = "Choose from Library";
if(result)
galleryOpen();
} else if (items[item].equals("Cancel")) {
dialog.dismiss();
}
}
});
builder.show();
}
public void cameraOpen() {
Intent openCamera = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
startActivityForResult(openCamera, 0);
}
private static int RESULT_LOAD_IMAGE = 1;
public static final int PICK_IMAGE = 1;
private void galleryOpen()
{
/** Intent intent = new Intent();
intent.setType("image/*");
intent.setAction(Intent.ACTION_GET_CONTENT);
startActivityForResult(Intent.createChooser(intent, "Select Picture"), PICK_IMAGE);
**/
Intent intent = new Intent(Intent.ACTION_PICK, android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
startActivityForResult(intent, SELECT_FILE);
System.out.println("this works at galleryopen()");
//intent.setType("image/*");
//intent.setAction(Intent.ACTION_GET_CONTENT);
//startActivityForResult(Intent.createChooser(intent, "Select File"),SELECT_FILE);
}
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
System.out.println("this works BEFORE requestcode == SELECT_FILE");
if (resultCode == Activity.RESULT_OK) {
if (requestCode == SELECT_FILE) {
Log.d("HELLO", "this works ");
System.out.println("this works at requestcode == SELECT_FILE");
galleryResult(data);
}
else if (requestCode == REQUEST_CAMERA) {
onCaptureImageResult(data);
}
}
}
private void galleryResult(Intent data) {
Bitmap thumbnail = (Bitmap) data.getExtras().get("data");
ByteArrayOutputStream bytes = new ByteArrayOutputStream();
thumbnail.compress(Bitmap.CompressFormat.JPEG, 90, bytes);
File destination = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES), "actualprofilepicture.jpg");
personalHome.this.getFilesDir().getAbsolutePath();
FileOutputStream fo;
try {
destination.createNewFile();
fo = new FileOutputStream(destination);
fo.write(bytes.toByteArray());
fo.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
setContentView(R.layout.personal_home);
profileimage.findViewById(R.id.profilepic1);
profileimage.setImageBitmap(thumbnail);
System.out.println("this works finally...or not");
Intent loadPersonal = new Intent(personalHome.this, personalHome.class);
startActivity(loadPersonal);
}
private void onCaptureImageResult(Intent data) {
Bitmap thumbnail = (Bitmap) data.getExtras().get("data");
ByteArrayOutputStream bytes = new ByteArrayOutputStream();
thumbnail.compress(Bitmap.CompressFormat.JPEG, 90, bytes);
/**destination of the file is set as PICTURES folder in the internal storage of device
* -- this stores the profile picture for when you next load the app
*/
File destination = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES),
"actualprofilepicture.jpg");
personalHome.this.getFilesDir().getAbsolutePath();
FileOutputStream fo;
try {
destination.createNewFile();
fo = new FileOutputStream(destination);
fo.write(bytes.toByteArray());
fo.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
setContentView(R.layout.personal_home);
profileimage = (ImageView) findViewById(R.id.profilepic1);
profileimage.setImageBitmap(thumbnail);
Intent loadPersonal = new Intent(personalHome.this, personalHome.class);
startActivity(loadPersonal);
}
}