我按照Kii Cloud教程创建和实现了一个对象，并尝试将其实现到我自己的应用程序中。它基本上做的是，当用户点击＆＃34; existingButton＆＃34;时，它会打开一个新活动，用户可以从库中选择一个图像并上传它。我在第二项活动中没有遇到任何问题，但第一项活动的uri来自＆＃34; null＆＃34;到第二个活动，我最终得到一个NullPointerException，因为我试图解析一个空字符串。我通过调试器检查了这个问题，发现问题出现在第一个活动＆＃34; onSaveCompleted＆＃34;方法。 if（异常== null）条件不符合，这基本上意味着我得到某种异常，我想。然后，如果不满足（例如，CloudExecutionException异常）条件。结果，它显示了我的主要if的其他条件的Toast。代码如下。谢谢你的帮助。
第一项活动：
public class SendNotePreActivity extends AppCompatActivity {
public static final String APP_BUCKET_NAME = "tutorial";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_send_note_pre);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
Button existingButton = (Button) findViewById(R.id.existingButton);
existingButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
KiiBucket bucket = Kii.bucket(APP_BUCKET_NAME);
KiiObject object = bucket.object();
object.set("deneme", 313131);
object.save(new KiiObjectCallBack() {
@Override
public void onSaveCompleted(int token, @NonNull KiiObject object,
Exception exception) {
if (exception == null) {
final String uri = object.toUri().toString();
SharedPreferences.Editor mEditor = getSharedPreferences("args", MODE_PRIVATE).edit();
mEditor.putString("uri", uri);
mEditor.apply();
Toast.makeText(SendNotePreActivity.this, "SUCCESSFUL", Toast.LENGTH_LONG).show();
} else {
if (exception instanceof CloudExecutionException) {
Toast.makeText(SendNotePreActivity.this, "Please choose an image", Toast.LENGTH_LONG).show();
} else {
Toast.makeText(SendNotePreActivity.this, "Please choose an image222", Toast.LENGTH_LONG).show();
}
}
}
});
Intent intent = new Intent(SendNotePreActivity.this, SendNoteActivity.class);
startActivity(intent);
}
});
}
}
第二项活动：
public class SendNoteActivity extends AppCompatActivity {
ImageView imagePreview;
private static final int PICK_IMAGE = 1;
String filePath = null;
String objectUri = null;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_send_note);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
imagePreview = (ImageView) findViewById(R.id.imagePreview);
Button chooseButton = (Button) findViewById(R.id.chooseButton);
chooseButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent();
intent.setType("image/*");
intent.setAction(Intent.ACTION_GET_CONTENT);
startActivityForResult(Intent.createChooser(intent, "Select Note"), PICK_IMAGE);
}
});
Button sendButton = (Button) findViewById(R.id.sendButton);
sendButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (filePath == null) {
Toast.makeText(SendNoteActivity.this, "Please choose an image", Toast.LENGTH_LONG).show();
} else {
uploadFile(filePath);
}
}
});
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode == PICK_IMAGE && resultCode == Activity.RESULT_OK && data != null) {
Uri selectedFileUri = data.getData();
imagePreview.setImageURI(selectedFileUri);
filePath = getFilePathByUri(selectedFileUri);
if (filePath == null) {
Toast.makeText(SendNoteActivity.this, "File does not exist", Toast.LENGTH_LONG).show();
return;
}
} else {
super.onActivityResult(requestCode, resultCode, data);
Toast.makeText(SendNoteActivity.this, "Picking failed", Toast.LENGTH_SHORT).show();
}
}
private String getFilePathByUri(Uri selectedFileUri) {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1) {
// Workaround of retrieving file image through ContentResolver
// for Android4.2 or later
String filePath = null;
FileOutputStream fos = null;
try {
Bitmap bmp = MediaStore.Images.Media.getBitmap(
SendNoteActivity.this.getContentResolver(), selectedFileUri);
String cacheDir = Environment.getExternalStorageDirectory()
.getAbsolutePath() + File.separator + "tutorialapp";
File createDir = new File(cacheDir);
if (!createDir.exists()) {
createDir.mkdir();
}
filePath = cacheDir + File.separator + "upload.jpg";
File file = new File(filePath);
fos = new FileOutputStream(file);
bmp.compress(Bitmap.CompressFormat.JPEG, 95, fos);
fos.flush();
fos.getFD().sync();
} catch (Exception e) {
filePath = null;
} finally {
if (fos != null) {
try {
fos.close();
} catch (Exception e) {
// Nothing to do
}
}
}
return filePath;
} else {
String[] filePathColumn = { MediaStore.MediaColumns.DATA };
Cursor cursor = SendNoteActivity.this.getContentResolver().query(
selectedFileUri, filePathColumn, null, null, null);
if (cursor == null)
return null;
try {
if (!cursor.moveToFirst())
return null;
int columnIndex = cursor.getColumnIndex(filePathColumn[0]);
if (columnIndex < 0) {
return null;
}
String picturePath = cursor.getString(columnIndex);
return picturePath;
} finally {
cursor.close();
}
}
}
private void uploadFile(String path) {
SharedPreferences prefs = getSharedPreferences("args", MODE_PRIVATE);
objectUri = prefs.getString("uri", "OLMADI AQ");
KiiObject object = KiiObject.createByUri(Uri.parse(objectUri));
File f = new File(path);
KiiUploader uploader = object.uploader(SendNoteActivity.this, f);
uploader.transferAsync(new KiiRTransferCallback() {
@Override
public void onStart(KiiRTransfer operator) {
}
@Override
public void onTransferCompleted(KiiRTransfer operator, Exception e) {
if (e == null) {
Toast.makeText(SendNoteActivity.this, "Successful", Toast.LENGTH_LONG).show();
} else {
Throwable cause = e.getCause();
if (cause instanceof CloudExecutionException)
Toast.makeText(SendNoteActivity.this, "Error", Toast.LENGTH_LONG).show();
else
Toast.makeText(SendNoteActivity.this, "Error2", Toast.LENGTH_LONG).show();
}
}
});
}
}
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FATAL EXCEPTION: main
Process: com.theoc.proto, PID: 8050
java.lang.NullPointerException: uriString
at android.net.Uri$StringUri.<init>(Uri.java:470)
at android.net.Uri$StringUri.<init>(Uri.java:460)
at android.net.Uri.parse(Uri.java:432)
at com.theoc.proto.SendNoteActivity.uploadFile(SendNoteActivity.java:163)
at com.theoc.proto.SendNoteActivity.access$000(SendNoteActivity.java:44)
at com.theoc.proto.SendNoteActivity$2.onClick(SendNoteActivity.java:82)
at android.view.View.performClick(View.java:4763)
at android.view.View$PerformClick.run(View.java:19821)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5272)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:909)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:704)
答案 0 :(得分：0)
将startActivity移动到onSaveCompleted，因为现在您在保存为finishec之前启动第二个活动