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我正在做一个关于包含推文的 ListView 的教程。它有效，但现在每次都崩溃。我检查了我的代码，它与教程中的完全相同。

public class MainActivity extends Activity {

    Button mBtnDownload;
    EditText mEtxtUsername;
    ProgressDialog mProgressDialog;

    TextView mTxtvUserNameTitle;
    TextView mTxtvUserName;
    TextView mTxtvUrlTitle;
    TextView mTxtvUrl;
    TextView mTxtvFavouritesCountTitle;
    TextView mTxtvFavouritesCount;
    TextView mTxtvDescriptionTitle;
    TextView mTxtvDescription;
    Button mBtnTweets;

    TwitterUser mTwitterUser;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.nicelayout);

        mBtnDownload = (Button) findViewById(R.id.btnDownload);
        mEtxtUsername = (EditText) findViewById(R.id.etxtUsername);

        mTxtvUserNameTitle = (TextView) findViewById(R.id.txtvUserNameTitle);
        mTxtvUserName = (TextView) findViewById(R.id.txtvUserName); 
        mTxtvUrlTitle = (TextView) findViewById(R.id.txtvUrlTitle); 
        mTxtvUrl = (TextView) findViewById(R.id.txtvUrl);

        mTxtvFavouritesCountTitle = (TextView) findViewById(R.id.txtvFavouritesCountTitle);
        mTxtvFavouritesCount = (TextView) findViewById(R.id.txtvFavouritesCount); 
        mTxtvDescriptionTitle = (TextView) findViewById(R.id.txtvDescriptionTitle); 
        mTxtvDescription = (TextView) findViewById(R.id.txtvDescription);

        mBtnTweets = (Button) findViewById(R.id.btnTweets);

        updateView();
    }

    public void downloadUserInfo(View view){
        if (view == mBtnDownload){
            String username = mEtxtUsername.getText().toString();
            if (username.length() > 0){
                    mProgressDialog = new ProgressDialog(this);
                    mProgressDialog.setMessage("Bezig met het ophalen van gegevens...");
                    mProgressDialog.show();
                    new DownloadUserInfoTask().execute();
            }
            else{
                Toast.makeText(this, "Voer een twitter gebruikersnaam in", Toast.LENGTH_LONG).show();
            }
        }
    }

    public void showTweets(View view){
        if (view == mBtnTweets){
            Intent intent = new Intent(this, TweetsActivity.class);
            intent.putExtra("twitter_user_name", mTwitterUser.getUserName());
            startActivity(intent);

        }
    }

    private DefaultHttpClient createHttpClient() {
        HttpParams my_httpParams = new BasicHttpParams();
        HttpConnectionParams.setConnectionTimeout(my_httpParams, 3000);
        SchemeRegistry registry = new SchemeRegistry();
        registry.register(new Scheme("http", PlainSocketFactory.getSocketFactory(), 80));
        ThreadSafeClientConnManager multiThreadedConnectionManager = new ThreadSafeClientConnManager(my_httpParams, registry);
        DefaultHttpClient httpclient = new DefaultHttpClient(multiThreadedConnectionManager, my_httpParams);
        return httpclient;
    }

    private void updateView(){
        if (mTwitterUser == null){
            mTxtvUrlTitle.setVisibility(View.INVISIBLE);
            mTxtvUrl.setVisibility(View.INVISIBLE);
            mTxtvUserNameTitle.setVisibility(View.INVISIBLE);
            mTxtvUserName.setVisibility(View.INVISIBLE);

            mTxtvFavouritesCountTitle.setVisibility(View.INVISIBLE);
            mTxtvFavouritesCount.setVisibility(View.INVISIBLE);
            mTxtvDescriptionTitle.setVisibility(View.INVISIBLE);
            mTxtvDescription.setVisibility(View.INVISIBLE);

            mBtnTweets.setVisibility(View.INVISIBLE);
        }
        else {
            mTxtvUrlTitle.setVisibility(View.VISIBLE);
            mTxtvUrl.setVisibility(View.VISIBLE);
            mTxtvUserNameTitle.setVisibility(View.VISIBLE);
            mTxtvUserName.setVisibility(View.VISIBLE);

            mTxtvFavouritesCountTitle.setVisibility(View.VISIBLE);
            mTxtvFavouritesCount.setVisibility(View.VISIBLE);
            mTxtvDescriptionTitle.setVisibility(View.VISIBLE);
            mTxtvDescription.setVisibility(View.VISIBLE);

            mBtnTweets.setVisibility(View.VISIBLE);

            mTxtvUrl.setText(mTwitterUser.getWebsite());
            mTxtvUserName.setText(mTwitterUser.getUserName());
            mTxtvFavouritesCount.setText(mTwitterUser.getFavouritesCount() + "");
            mTxtvDescription.setText(mTwitterUser.getDescription());
        }
    }

    private class DownloadUserInfoTask extends AsyncTask<Void, Void, Void> {

        int mStatusCode = 0;
        String mResultString;
        Exception mConnectionException;

        @Override
        protected Void doInBackground(Void... args) {
            String username = mEtxtUsername.getText().toString();
            String encodedUserName= "";
            try {
                encodedUserName= URLEncoder.encode(username, "utf-8");
            } catch (UnsupportedEncodingException e1) {
                // TODO Auto-generated catch block
                e1.printStackTrace();
            }

            String fetchUrl = "http://api.twitter.com/1/users/show.json?screen_name=" + encodedUserName;

            DefaultHttpClient httpclient = createHttpClient();
            HttpGet httpget = new HttpGet(fetchUrl);

            try {
                HttpResponse response = httpclient.execute(httpget);
                StatusLine statusLine = response.getStatusLine();
                mStatusCode  = statusLine.getStatusCode();

                if (mStatusCode == 200){
                    mResultString = EntityUtils.toString(response.getEntity());
                }
            } catch (ClientProtocolException e) {
                e.printStackTrace();
                mConnectionException = e;
            } catch (IOException e) {
                e.printStackTrace();
                mConnectionException = e;
            }
            return null;
        }

        @Override
        protected void onPostExecute(Void arg) {
            mProgressDialog.dismiss();
            if (mStatusCode  == 200){
                mTwitterUser = new TwitterUser(mResultString);
                updateView();
            }
            else if (mStatusCode  == 404){
                Toast.makeText(MainActivity.this, "De gevraagde gebruiker bestaat niet.", Toast.LENGTH_LONG).show();
                mTwitterUser = null;
                updateView();
            }
            else if (mStatusCode > 0){
                Toast.makeText(MainActivity.this, "Er is in verbindingsfout opgetreden met foutcode " + mStatusCode, Toast.LENGTH_LONG).show();
                mTwitterUser = null;
                updateView();
            }
            else {
                Toast.makeText(MainActivity.this, "Gegevens konden niet worden opgehaald. Controleer uw internetverbinding en probeer het opnieuw (" +mConnectionException.toString() + ")" , Toast.LENGTH_LONG).show();
                mTwitterUser = null;
                updateView();
            }
        }
    }
}



public class TwitterUser {

    String mUserName;
    String mWebsite;
    String mDescription;
    int mFavouritesCount;

    public TwitterUser(String jsonString){
        try {
            JSONObject jSONObject = new JSONObject(jsonString);
            mUserName = jSONObject.optString("screen_name");
            mWebsite = jSONObject.optString("url");
            mDescription = jSONObject.optString("description");
            mFavouritesCount = jSONObject.optInt("favourites_count");
        } catch (JSONException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

    public String getUserName(){
        return mUserName;
    }

    public String getWebsite(){
        return mWebsite;
    }

    public String getDescription(){
        return mDescription;
    }

    public int getFavouritesCount(){
        return mFavouritesCount;
    }
}



public class TweetsActivity extends Activity {

    TextView mTxtvTitle;

    ProgressDialog mProgressDialog;
    String mUserName;

    ArrayList<Tweet> mTweets;
    ListView mLvTweets;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.tweets);

        mTxtvTitle = (TextView) findViewById(R.id.txtvTitle);
        mLvTweets = (ListView) findViewById(R.id.lvTweets);

        Intent intent = getIntent();
        Bundle extrasBundle = intent.getExtras();
        mUserName = extrasBundle.getString("twitter_user_name");

        updateView();

        startDownloadingTweets();
    }

    private void updateView() {
        mTxtvTitle.setText(mUserName);

        if (mTweets != null){
            TweetsListAdapter tweetsListAdapter = new TweetsListAdapter(this, mTweets);
            mLvTweets.setAdapter(tweetsListAdapter);
        }
    }

    private void startDownloadingTweets() {
        mProgressDialog = new ProgressDialog(this);
        mProgressDialog.setMessage("Bezig met het ophalen van gegevens...");
        mProgressDialog.show();
        new DownloadTweetsTask().execute();
    }

    private DefaultHttpClient createHttpClient() {
        HttpParams my_httpParams = new BasicHttpParams();
        HttpConnectionParams.setConnectionTimeout(my_httpParams, 3000);
        SchemeRegistry registry = new SchemeRegistry();
        registry.register(new Scheme("http", PlainSocketFactory.getSocketFactory(), 80));
        ThreadSafeClientConnManager multiThreadedConnectionManager = new ThreadSafeClientConnManager(my_httpParams, registry);
        DefaultHttpClient httpclient = new DefaultHttpClient(multiThreadedConnectionManager, my_httpParams);
        return httpclient;
    }

    private class DownloadTweetsTask extends AsyncTask<Void, Void, Void> {

        int mStatusCode = 0;
        String mResultString;
        Exception mConnectionException;

        @Override
        protected Void doInBackground(Void... args) {
            String encodedUserName= "";
            try {
                encodedUserName= URLEncoder.encode(mUserName, "utf-8");
            } catch (UnsupportedEncodingException e) {
                e.printStackTrace();
            }

            String fetchUrl = "http://api.twitter.com/1/statuses/user_timeline.json?include_rts=true&count=30&screen_name=" + encodedUserName;

            DefaultHttpClient httpclient = createHttpClient();
            HttpGet httpget = new HttpGet(fetchUrl);

            try {
                HttpResponse response = httpclient.execute(httpget);
                StatusLine statusLine = response.getStatusLine();
                mStatusCode  = statusLine.getStatusCode();

                if (mStatusCode == 200){
                    mResultString = EntityUtils.toString(response.getEntity());
                }
            } catch (ClientProtocolException e) {
                e.printStackTrace();
                mConnectionException = e;
            } catch (IOException e) {
                e.printStackTrace();
                mConnectionException = e;
            }
            return null;
        }

        @Override
        protected void onPostExecute(Void arg) {
            mProgressDialog.dismiss();
            if (mStatusCode  == 200){
                processResults(mResultString);
                updateView();
            }
            else if (mStatusCode  == 401){
                Toast.makeText(TweetsActivity.this, "De timeline van deze gebruiker is niet publiek toegankelijk.", Toast.LENGTH_LONG).show();
            }
            else if (mStatusCode > 0){
                Toast.makeText(TweetsActivity.this, "Er is in verbindingsfout opgetreden met foutcode " + mStatusCode, Toast.LENGTH_LONG).show();
            }
            else {
                Toast.makeText(TweetsActivity.this, "Gegevens konden niet worden opgehaald. Controleer uw internetverbinding en probeer het opnieuw (" +mConnectionException.toString() + ")" , Toast.LENGTH_LONG).show();
            }
        }

    }   

    private void processResults(String resultString) {
        mTweets = new ArrayList<Tweet>();
        try {
            JSONArray jSONArray = new JSONArray(resultString);
            for (int counter = 0; counter < jSONArray.length() ; counter ++){
                JSONObject jSONObject = jSONArray.getJSONObject(counter);
                Tweet tweet = new Tweet(jSONObject);
                mTweets.add(tweet);
            }
        } catch (JSONException e) {
            e.printStackTrace();
        }
    }


}



public class TweetsListAdapter extends BaseAdapter {

    ArrayList<Tweet> mTweets;
    LayoutInflater mInflater;

    public TweetsListAdapter(Context context, ArrayList<Tweet> tweets){
        mTweets = new ArrayList<Tweet>();
        mTweets.addAll(tweets);
        notifyDataSetChanged();
        mInflater = LayoutInflater.from(context);
    }

    public int getCount() {
        return mTweets.size();
    }

    public Tweet getItem(int position) {
        return mTweets.get(position);
    }

    public long getItemId(int position) {
        return position;
    }

    public View getView(final int position, View convertView, ViewGroup parent) {
        ViewHolder holder;

        if (convertView == null) {
            convertView = mInflater.inflate(R.layout.tweet_listitem, null);

            holder = new ViewHolder();
            holder.mTxtvText = (TextView) convertView.findViewById(R.id.txtvText);
            holder.mTxtvCreatedAt = (TextView) convertView.findViewById(R.id.txtvCreatedAt);

            convertView.setTag(holder);
        } else {
            holder = (ViewHolder) convertView.getTag();
        }

        Tweet tweet = getItem(position);

        holder.mTxtvText.setText(tweet.getText());

        SimpleDateFormat simpleDateFormat = new SimpleDateFormat("dd-MM-yyyy HH:mm");
        String dateString = simpleDateFormat.format(tweet.getCreatedAt());
        holder.mTxtvCreatedAt.setText(dateString);

        return convertView;
    }

    private class ViewHolder {
        TextView mTxtvText;
        TextView mTxtvCreatedAt;
    }
}



public class Tweet {

    Date mCreatedAt;
    String mText;

    static SimpleDateFormat sEnglishSimpleDateFormat;

    public Tweet(JSONObject jSONObject){
        String dateString = jSONObject.optString("created_at");

            if (sEnglishSimpleDateFormat == null){
                Locale englishLocale = Locale.ENGLISH;
                sEnglishSimpleDateFormat = new SimpleDateFormat("EEE MMM dd HH:mm:ss ZZZZZ yyyy", englishLocale);
            }

        try {
            mCreatedAt = sEnglishSimpleDateFormat.parse(dateString);
        } catch (ParseException e) {
            e.printStackTrace();
        }

        mText = jSONObject.optString("text");
    }

    public Date getCreatedAt(){
        return mCreatedAt;
    }

    public String getText(){
        return mText;
    }
}

以及发生的错误：

10-18 21:22:49.478: D/dalvikvm(390): GC freed 4935 objects / 312200
bytes in 101ms 10-18 21:22:51.628: I/Resources(390): Loaded time zone
names for en_US in 1769ms. 10-18 21:22:51.938: D/dalvikvm(390): GC
freed 2918 objects / 178312 bytes in 245ms 10-18 21:22:51.948:
D/dalvikvm(390): threadid=17 wakeup: interrupted 10-18 21:22:54.958:
D/AndroidRuntime(390): Shutting down VM 10-18 21:22:54.958:
W/dalvikvm(390): threadid=3: thread exiting with uncaught exception
(group=0x4001b188) 10-18 21:22:54.968: E/AndroidRuntime(390): Uncaught
handler: thread main exiting due to uncaught exception 10-18
21:22:54.988: E/AndroidRuntime(390): java.lang.IllegalStateException:
Could not execute method of the activity 10-18 21:22:54.988:
E/AndroidRuntime(390):  at android.view.View$1.onClick(View.java:2031)
10-18 21:22:54.988: E/AndroidRuntime(390):  at
android.view.View.performClick(View.java:2364) 10-18 21:22:54.988:
E/AndroidRuntime(390):  at
android.view.View.onTouchEvent(View.java:4179) 10-18 21:22:54.988:
E/AndroidRuntime(390):  at
android.widget.TextView.onTouchEvent(TextView.java:6541) 10-18
21:22:54.988: E/AndroidRuntime(390):    at
android.view.View.dispatchTouchEvent(View.java:3709) 10-18
21:22:54.988: E/AndroidRuntime(390):    at
android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884) 10-18
21:22:54.988: E/AndroidRuntime(390):    at
android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884) 10-18
21:22:54.988: E/AndroidRuntime(390):    at
android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884) 10-18
21:22:54.988: E/AndroidRuntime(390):    at
android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884) 10-18
21:22:54.988: E/AndroidRuntime(390):    at
android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884) 10-18
21:22:54.988: E/AndroidRuntime(390):    at
com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:1659)
10-18 21:22:54.988: E/AndroidRuntime(390):  at
com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1107)
10-18 21:22:54.988: E/AndroidRuntime(390):  at
android.app.Activity.dispatchTouchEvent(Activity.java:2061) 10-18
21:22:54.988: E/AndroidRuntime(390):    at
com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:1643)
10-18 21:22:54.988: E/AndroidRuntime(390):  at
android.view.ViewRoot.handleMessage(ViewRoot.java:1691) 10-18
21:22:54.988: E/AndroidRuntime(390):    at
android.os.Handler.dispatchMessage(Handler.java:99) 10-18
21:22:54.988: E/AndroidRuntime(390):    at
android.os.Looper.loop(Looper.java:123) 10-18 21:22:54.988:
E/AndroidRuntime(390):  at
android.app.ActivityThread.main(ActivityThread.java:4363) 10-18
21:22:54.988: E/AndroidRuntime(390):    at
java.lang.reflect.Method.invokeNative(Native Method) 10-18
21:22:54.988: E/AndroidRuntime(390):    at
java.lang.reflect.Method.invoke(Method.java:521) 10-18 21:22:54.988:
E/AndroidRuntime(390):  at
com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
10-18 21:22:54.988: E/AndroidRuntime(390):  at
com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618) 10-18
21:22:54.988: E/AndroidRuntime(390):    at
dalvik.system.NativeStart.main(Native Method) 10-18 21:22:54.988:
E/AndroidRuntime(390): Caused by:
java.lang.reflect.InvocationTargetException 10-18 21:22:54.988:
E/AndroidRuntime(390):  at
com.example.twittertest.MainActivity.showTweets(MainActivity.java:93)
10-18 21:22:54.988: E/AndroidRuntime(390):  at
java.lang.reflect.Method.invokeNative(Native Method) 10-18
21:22:54.988: E/AndroidRuntime(390):    at
java.lang.reflect.Method.invoke(Method.java:521) 10-18 21:22:54.988:
E/AndroidRuntime(390):  at android.view.View$1.onClick(View.java:2026)
10-18 21:22:54.988: E/AndroidRuntime(390):  ... 22 more 10-18
21:22:54.988: E/AndroidRuntime(390): Caused by:
android.content.ActivityNotFoundException: Unable to find explicit
activity class
{com.example.twittertest/com.example.twittertest.TweetsActivity}; have
you declared this activity in your AndroidManifest.xml? 10-18
21:22:54.988: E/AndroidRuntime(390):    at
android.app.Instrumentation.checkStartActivityResult(Instrumentation.java:1404)
10-18 21:22:54.988: E/AndroidRuntime(390):  at
android.app.Instrumentation.execStartActivity(Instrumentation.java:1378)
10-18 21:22:54.988: E/AndroidRuntime(390):  at
android.app.Activity.startActivityForResult(Activity.java:2749) 10-18
21:22:54.988: E/AndroidRuntime(390):    at
android.app.Activity.startActivity(Activity.java:2855) 10-18
21:22:54.988: E/AndroidRuntime(390):    ... 26 more 10-18 21:22:55.031:
I/dalvikvm(390): threadid=7: reacting to signal 3 10-18 21:22:55.031:
E/dalvikvm(390): Unable to open stack trace file
'/data/anr/traces.txt': Permission denied 10-18 21:22:57.828:
I/Process(390): Sending signal. PID: 390 SIG: 9
4

2 回答 2

1

com.example.twittertest.TweetsActivity正如您的错误日志告诉您的那样，在您的清单中声明。

10-18 21:22:54.988: E/AndroidRuntime(390): Caused by: android.content.ActivityNotFoundException: Unable to find explicit activity class { com.example.twittertest/com.example.twittertest.TweetsActivity}; 您是否在 AndroidManifest.xml 中声明了此活动？

像这样：

<activity android:name="com.example.twittertest.TweetsActivity" />
于 2012-10-18T21:44:37.023 回答
0

错误出现在您从 logcat 发布的字符串中。

Caused by: android.content.ActivityNotFoundException: Unable to find explicit activity class {com.example.twittertest/com.example.twittertest.TweetsActivity}; have you declared this activity in your AndroidManifest.xml?

该活动TweetsActivity未在您的清单中声明。您必须打开项目根目录中的 AndroidManifest.xml 文件。在这个文件中，放置声明：

<activity
    android:name="com.example.twittertest.TweetsActivity">
</activity>

<aplication>标签内。

于 2012-10-18T21:47:52.567 回答