按鈕將我重定向到Android Studio中的MainActivity，而不是打開新活動

Question

我目前遇到問題，我認為這可能是我的選擇。 在Android Studio中：我已經制作了一個應用程序，目前，應該從一個頁面（AccountListActivity）上單擊一個按鈕即可重定向到另一頁面（SelectSNActivity）。 之前效果不錯，但是最近我在SelectSNActivity上添加了Google+登錄選項后，該按鈕將無法使用，而是將我重定向回起始頁面。

我想知道代碼的問題是否可能在AccountListActivity中（因為這是按鈕從中啟動Intent的地方。

我沒有任何錯誤，並且能夠在模擬器和實際設備上運行該應用程序。 如果您能夠發現錯誤的根源，或者希望我過去發送其他文件，請隨時在下面評論或發表，非常感謝。

這里是：

.java代碼的AccountListActivity

package com.instigate.aggregator06;

import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.ListView;
import android.widget.TextView;

import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Hashtable;
import java.util.Map;


public class AccountListActivity extends AppCompatActivity {

public HashMap accountList = new HashMap();



@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_account_list);

    TextView emptyview = (TextView) findViewById(R.id.empty);
    ListView accountslist=(ListView) findViewById(R.id.list);
    emptyview.setVisibility(View.VISIBLE);
    accountslist.setVisibility(View.GONE);


    /*if (accountList.length() == 0)
    {
        emptyview.setVisibility(View.GONE);
        accountslist.setVisibility(View.VISIBLE);
    }
    else
    {
        accountslist.setVisibility(View.VISIBLE);
        emptyview.setVisibility(View.GONE);
    } */

}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.menu_account_list, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();

    //noinspection SimplifiableIfStatement
    if (id == R.id.action_settings) {
        return true;
    }

    return super.onOptionsItemSelected(item);

}

public void goToSelectSNPage(View view)
{
    Intent k = new Intent(AccountListActivity.this,SelectSNActivity.class);
    startActivity(k);
}

}

xml代碼AccountListActivity

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingLeft="8dp"
android:paddingRight="8dp"
android:id="@+id/accountPage">

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:textAppearance="?android:attr/textAppearanceLarge"
    android:text="@string/accountPageHeader"
    android:id="@+id/accountPageHeader"
    android:layout_gravity="center_horizontal"
    android:layout_alignParentTop="true"
    android:layout_centerHorizontal="true"
    android:textSize="36sp"/>

<LinearLayout
    android:layout_below="@id/accountPageHeader"

    android:paddingLeft="8dp"
    android:paddingRight="8dp"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:orientation="vertical">


    <TextView android:id="@+id/empty"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:text="@string/noAccounts"
        android:visibility="visible"
        android:textSize="24sp"
        />

    <ScrollView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/scrollView"
        android:visibility="gone">

        <ListView android:id="@+id/list"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"

            />
    </ScrollView>

    <Button android:id="@+id/addAccount"
        android:text="@string/addAccount"
        android:layout_height="wrap_content"
        android:layout_width="wrap_content"
        android:onClick="goToSelectSNPage"/>


</LinearLayout>

</RelativeLayout>

---

.java代碼以用於SelectSNActivity

package com.instigate.aggregator06;

import android.content.DialogInterface;
import android.content.Intent;
import android.content.IntentSender;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import android.widget.TextView;
import android.widget.Toast;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.GooglePlayServicesUtil;
import com.google.android.gms.common.Scopes;
import com.google.android.gms.common.SignInButton;
import com.google.android.gms.common.api.GoogleApiClient;
import com.google.android.gms.common.api.Scope;
import com.google.android.gms.plus.Plus;
/**
 * Minimal activity demonstrating basic Google Sign-In.
 */
public class SelectSNActivity extends AppCompatActivity implements
        View.OnClickListener,
        GoogleApiClient.ConnectionCallbacks,
        GoogleApiClient.OnConnectionFailedListener {
    private static final String TAG = "SelectSNActivity";
    /* RequestCode for resolutions involving sign-in */
    private static final int RC_SIGN_IN = 9001;
    /* Keys for persisting instance variables in savedInstanceState */
    private static final String KEY_IS_RESOLVING = "is_resolving";
    private static final String KEY_SHOULD_RESOLVE = "should_resolve";
    /* Client for accessing Google APIs */
    private GoogleApiClient mGoogleApiClient;
    /* View to display current status (signed-in, signed-out, disconnected, etc) */
    private TextView mStatus;
    /* Is there a ConnectionResult resolution in progress? */
    private boolean mIsResolving = false;
    /* Should we automatically resolve ConnectionResults when possible? */
    private boolean mShouldResolve = false;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
// Restore from saved instance state
// [START restore_saved_instance_state]
        if (savedInstanceState != null) {
            mIsResolving = savedInstanceState.getBoolean(KEY_IS_RESOLVING);
            mShouldResolve = savedInstanceState.getBoolean(KEY_SHOULD_RESOLVE);
        }
// [END restore_saved_instance_state]
// Set up button click listeners
        findViewById(R.id.googleSignInBtn).setOnClickListener(this);
        //findViewById(R.id.sign_out_button).setOnClickListener(this);
        //findViewById(R.id.disconnect_button).setOnClickListener(this);
// Large sign-in
        ((SignInButton) findViewById(R.id.googleSignInBtn)).setSize(SignInButton.SIZE_WIDE);
// Start with sign-in button disabled until sign-in either succeeds or fails
        findViewById(R.id.googleSignInBtn).setEnabled(false);
// Set up view instances
        //mStatus = (TextView) findViewById(R.id.status);
// [START create_google_api_client]
// Build GoogleApiClient with access to basic profile
        mGoogleApiClient = new GoogleApiClient.Builder(this)
                .addConnectionCallbacks(this)
                .addOnConnectionFailedListener(this)
                .addApi(Plus.API)
                .addScope(new Scope(Scopes.PROFILE))
                .build();
// [END create_google_api_client]
    }
    private void updateUI(boolean isSignedIn) {
        if (isSignedIn) {
// Show signed-in user's name
            String name = Plus.PeopleApi.getCurrentPerson(mGoogleApiClient).getDisplayName();
            mStatus.setText(getString(R.string.signed_in_fmt, name));
// Set button visibility
            findViewById(R.id.googleSignInBtn).setVisibility(View.GONE);
            //findViewById(R.id.sign_out_and_disconnect).setVisibility(View.VISIBLE);
        } else {
// Show signed-out message
            mStatus.setText(R.string.signed_out);
// Set button visibility
            findViewById(R.id.googleSignInBtn).setEnabled(true);
            findViewById(R.id.googleSignInBtn).setVisibility(View.VISIBLE);
            //findViewById(R.id.sign_out_and_disconnect).setVisibility(View.GONE);
        }
    }
    // [START on_start_on_stop]
    @Override
    protected void onStart() {
        super.onStart();
        mGoogleApiClient.connect();
    }
    @Override
    protected void onStop() {
        super.onStop();
        mGoogleApiClient.disconnect();
    }
    // [END on_start_on_stop]
// [START on_save_instance_state]
    @Override
    protected void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        outState.putBoolean(KEY_IS_RESOLVING, mIsResolving);
        outState.putBoolean(KEY_SHOULD_RESOLVE, mIsResolving);
    }
    // [END on_save_instance_state]
// [START on_activity_result]
    @Override
    public void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        Log.d(TAG, "onActivityResult:" + requestCode + ":" + resultCode + ":" + data);
        if (requestCode == RC_SIGN_IN) {
// If the error resolution was not successful we should not resolve further errors.
            if (resultCode != RESULT_OK) {
                mShouldResolve = false;
            }
            mIsResolving = false;
            mGoogleApiClient.connect();
        }
    }
    // [END on_activity_result]
    @Override
    public void onConnected(Bundle bundle) {
// onConnected indicates that an account was selected on the device, that the selected
// account has granted any requested permissions to our app and that we were able to
// establish a service connection to Google Play services.
        Log.d(TAG, "onConnected:" + bundle);
// Show the signed-in UI
        updateUI(true);
    }
    @Override
    public void onConnectionSuspended(int i) {
// The connection to Google Play services was lost. The GoogleApiClient will automatically
// attempt to re-connect. Any UI elements that depend on connection to Google APIs should
// be hidden or disabled until onConnected is called again.
        Log.w(TAG, "onConnectionSuspended:" + i);
    }
    // [START on_connection_failed]
    @Override
    public void onConnectionFailed(ConnectionResult connectionResult) {
// Could not connect to Google Play Services.  The user needs to select an account,
// grant permissions or resolve an error in order to sign in. Refer to the javadoc for
// ConnectionResult to see possible error codes.
        Log.d(TAG, "onConnectionFailed:" + connectionResult);
        if (!mIsResolving && mShouldResolve) {
            if (connectionResult.hasResolution()) {
                try {
                    connectionResult.startResolutionForResult(this, RC_SIGN_IN);
                    mIsResolving = true;
                } catch (IntentSender.SendIntentException e) {
                    Log.e(TAG, "Could not resolve ConnectionResult.", e);
                    mIsResolving = false;
                    mGoogleApiClient.connect();
                }
            } else {
// Could not resolve the connection result, show the user an
// error dialog.
                showErrorDialog(connectionResult);
            }
        } else {
 //Show the signed-out UI
            updateUI(false);
        }
    }
    // [END on_connection_failed]
    private void showErrorDialog(ConnectionResult connectionResult) {
        int errorCode = connectionResult.getErrorCode();
        if (GooglePlayServicesUtil.isUserRecoverableError(errorCode)) {
// Show the default Google Play services error dialog which may still start an intent
// on our behalf if the user can resolve the issue.
            GooglePlayServicesUtil.getErrorDialog(errorCode, this, RC_SIGN_IN,
                    new DialogInterface.OnCancelListener() {
                        @Override
                        public void onCancel(DialogInterface dialog) {
                            mShouldResolve = false;
                            updateUI(false);
                        }
                    }).show();
        } else {
// No default Google Play Services error, display a message to the user.
            String errorString = getString(R.string.play_services_error_fmt, errorCode);
            Toast.makeText(this, errorString, Toast.LENGTH_SHORT).show();
            mShouldResolve = false;
            updateUI(false);
        }
    }
    @Override
    public void onClick(View v) {
        switch (v.getId()) {
            case R.id.googleSignInBtn:
// User clicked the sign-in button, so begin the sign-in process and automatically
// attempt to resolve any errors that occur.
                mStatus.setText(R.string.signing_in);
// [START sign_in_clicked]
                mShouldResolve = true;
                mGoogleApiClient.connect();
// [END sign_in_clicked]
                break;
            /*case R.id.sign_out_button:
// Clear the default account so that GoogleApiClient will not automatically
// connect in the future.
// [START sign_out_clicked]
                if (mGoogleApiClient.isConnected()) {
                    Plus.AccountApi.clearDefaultAccount(mGoogleApiClient);
                    mGoogleApiClient.disconnect();
                }
// [END sign_out_clicked]
                updateUI(false);
                break;
            case R.id.disconnect_button:
// Revoke all granted permissions and clear the default account.  The user will have
// to pass the consent screen to sign in again.
// [START disconnect_clicked]
                if (mGoogleApiClient.isConnected()) {
                    Plus.AccountApi.clearDefaultAccount(mGoogleApiClient);
                    Plus.AccountApi.revokeAccessAndDisconnect(mGoogleApiClient);
                    mGoogleApiClient.disconnect();
                }
// [END disconnect_clicked]
                updateUI(false);
                break;*/
        }
    }

    public void goToSignInPage(View view)
    {
        Intent j = new Intent(SelectSNActivity.this, SignInActivity.class);
        startActivity(j);
    }

}

SelectSNActivity的xml代碼

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
    android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin"
    tools:context="com.instigate.aggregator06.SelectSNActivity"
    android:orientation="vertical"
    android:id="@+id/SelectSNActivity"
    android:weightSum="1">


    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceLarge"
        android:text="@string/selectSocialNetwork"
        android:id="@+id/selectSocialNetworkHeader"
        android:textStyle="bold"
        android:textSize="36sp"
        android:layout_gravity="center_horizontal"
        />

    <com.google.android.gms.common.SignInButton
        android:id="@+id/googleSignInBtn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/fbBtn"
        android:id="@+id/fbBtn"
        android:onClick="goToSignInPage"/>

</LinearLayout>

請注意，在使用Heisenberg的修復程序之后，我運行了該應用程序。 它會打開SelectSNActivity，但它會快速退出並自行返回MainActivity頁面。 這是我了解的兩個錯誤：

com.instigate.aggregator06.SelectSNActivity.updateUI(SelectSNActivity.java:83)

指的是

// Show signed-out message
            mStatus.setText(R.string.signed_out);

和

com.instigate.aggregator06.SelectSNActivity.onConnectionFailed(SelectSNActivity.java:165)

指的是

/ Could not resolve the connection result, show the user an
// error dialog.
          showErrorDialog(connectionResult);
 }
      } else {
 //Show the signed-out UI
            updateUI(false);           <--------- this line
    }
}

這是整個錯誤日志

07-21 16:47:46.572      138-507/? E/ALSAModule﹕ buffersize: 6144, periodsize:2048
07-21 16:47:46.582      138-507/? E/ALSAModule﹕ audio type flag: 0
07-21 16:47:46.582      138-507/? E/ALSAModule﹕ buffersize: 6144, periodsize:2048
07-21 16:47:46.582      138-507/? E/ALSAModule﹕ audio type flag: 0
07-21 16:48:00.012      515-529/system_process E/WindowManager﹕ Starting window AppWindowToken{4202bd70 token=Token{41cfb398 ActivityRecord{41bf3338 u0 com.ttxapps.wifiadb/.MainActivity t40}}} timed out
07-21 16:48:06.972      132-444/? E/FrameworkListener﹕ read() failed (Connection reset by peer)
07-21 16:48:21.062  23495-23495/? E/memtrack﹕ Couldn't load memtrack module (No such file or directory)
07-21 16:48:21.062  23495-23495/? E/android.os.Debug﹕ failed to load memtrack module: -2
07-21 16:48:33.862      860-860/com.google.process.gapps E/NetworkScheduler.SchedulerReceiver﹕ Invalid parameter app
07-21 16:48:33.862      860-860/com.google.process.gapps E/NetworkScheduler.SchedulerReceiver﹕ Invalid package name : Perhaps you didn't include a PendingIntent in the extras?
07-21 16:48:33.982      860-860/com.google.process.gapps E/NetworkScheduler.SchedulerReceiver﹕ Invalid parameter app
07-21 16:48:33.982      860-860/com.google.process.gapps E/NetworkScheduler.SchedulerReceiver﹕ Invalid package name : Perhaps you didn't include a PendingIntent in the extras?
07-21 16:48:34.852  23641-23641/? E/memtrack﹕ Couldn't load memtrack module (No such file or directory)
07-21 16:48:34.852  23641-23641/? E/android.os.Debug﹕ failed to load memtrack module: -2
07-21 16:48:35.522  23177-23177/com.ttxapps.wifiadb E/WifiADB﹕ IabPurchase: failed to query inventory: IabResult: Error refreshing inventory (querying prices of items). (response: 6:Error)
07-21 16:48:39.632      138-507/? E/ALSAModule﹕ buffersize: 6144, periodsize:2048
07-21 16:48:39.632      138-507/? E/ALSAModule﹕ audio type flag: 0
07-21 16:48:39.642      138-507/? E/ALSAModule﹕ buffersize: 6144, periodsize:2048
07-21 16:48:39.642      138-507/? E/ALSAModule﹕ audio type flag: 0
07-21 16:48:41.302  23657-23657/com.instigate.aggregator06 E/AndroidRuntime﹕ FATAL EXCEPTION: main
    Process: com.instigate.aggregator06, PID: 23657
    java.lang.NullPointerException
            at com.instigate.aggregator06.SelectSNActivity.updateUI(SelectSNActivity.java:83)
            at com.instigate.aggregator06.SelectSNActivity.onConnectionFailed(SelectSNActivity.java:165)
            at com.google.android.gms.common.internal.zzj.zzh(Unknown Source)
            at com.google.android.gms.common.api.zze.zzd(Unknown Source)
            at com.google.android.gms.common.api.zze.zza(Unknown Source)
            at com.google.android.gms.common.api.zze.zza(Unknown Source)
            at com.google.android.gms.common.api.zze$zzb$1.run(Unknown Source)
            at android.os.Handler.handleCallback(Handler.java:733)
            at android.os.Handler.dispatchMessage(Handler.java:95)
            at android.os.Looper.loop(Looper.java:136)
            at android.app.ActivityThread.main(ActivityThread.java:5017)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:515)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:794)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:610)
            at dalvik.system.NativeStart.main(Native Method)

Answer 1

您已經設置了setContentView（R.layout.activity_main）; 在SelectSNActivity的oncreate（）中。 將其替換為setContentView（R.layout.activity_select_sn）;