Question

我的启动活动代码是：

package com.example.hp_pc.earnmebucks;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.widget.ImageView;
import android.widget.LinearLayout;

public class SplashActivity extends AppCompatActivity {
    Thread splashTread;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_splash);
        Thread timerThread = new Thread() {
            public void run() {
                try {
                    sleep(3000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                } finally {
                    Intent intent = new Intent(SplashActivity.this, Login.class);
                    startActivity(intent);
                }
            }
        };
        timerThread.start();
    }
}

我的Login.java代码是：

package com.example.hp_pc.earnmebucks;

import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.support.annotation.NonNull;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.TextView;
import android.widget.Toast;

import com.google.android.gms.auth.api.Auth;
import com.google.android.gms.auth.api.signin.GoogleSignInAccount;
import com.google.android.gms.auth.api.signin.GoogleSignInOptions;
import com.google.android.gms.auth.api.signin.GoogleSignInResult;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.SignInButton;
import com.google.android.gms.common.api.GoogleApiClient;
import com.google.android.gms.common.api.OptionalPendingResult;
import com.google.android.gms.common.api.ResultCallback;

public class Login extends  AppCompatActivity   implements
        View.OnClickListener,
        GoogleApiClient.OnConnectionFailedListener {

    private static final String TAG = MainActivity.class.getSimpleName();
    private static final int RC_SIGN_IN = 007;

    private GoogleApiClient mGoogleApiClient;
    private ProgressDialog mProgressDialog;

    private SignInButton btnSignIn;
    private Button btnSignOut, btnRevokeAccess;
    private LinearLayout llProfileLayout;
    private ImageView imgProfilePic;
    private TextView txtName, txtEmail;


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

        super.getIntent();
        btnSignIn = (SignInButton) findViewById(R.id.sign_in_button);

        btnSignIn.setOnClickListener(this);



        GoogleSignInOptions gso = new GoogleSignInOptions.Builder(GoogleSignInOptions.DEFAULT_SIGN_IN)
                .requestEmail()
                .build();

        mGoogleApiClient = new GoogleApiClient.Builder(this)
                .enableAutoManage(this, this)
                .addApi(Auth.GOOGLE_SIGN_IN_API, gso)
                .build();

        // Customizing G+ button
        btnSignIn.setSize(SignInButton.SIZE_STANDARD);
        btnSignIn.setScopes(gso.getScopeArray());
    }


    private void signIn() {
        Intent signInIntent = Auth.GoogleSignInApi.getSignInIntent(mGoogleApiClient);
        startActivityForResult(signInIntent, RC_SIGN_IN);
    }



        private void handleSignInResult(GoogleSignInResult result) {
            Log.d(TAG, "handleSignInResult:" + result.isSuccess());
            if (result.isSuccess()) {
                // Signed in successfully, show authenticated UI.
                GoogleSignInAccount acct = result.getSignInAccount();

                Log.e(TAG, "display name: " + acct.getDisplayName());



                updateUI(true);
            } else {
                // Signed out, show unauthenticated UI.
                updateUI(false);
            }
        }

        @Override
        public void onClick(View v) {
            int id = v.getId();

            switch (id) {
                case R.id.sign_in_button:
                    signIn();
                    break;


            }
        }

        @Override
        public void onActivityResult(int requestCode, int resultCode, Intent data) {
            super.onActivityResult(requestCode, resultCode, data);

            // Result returned from launching the Intent from GoogleSignInApi.getSignInIntent(...);
            if (requestCode == RC_SIGN_IN) {
                GoogleSignInResult result = Auth.GoogleSignInApi.getSignInResultFromIntent(data);
                handleSignInResult(result);
            }
        }

        @Override
        public void onStart() {
            super.onStart();

            OptionalPendingResult<GoogleSignInResult> opr = Auth.GoogleSignInApi.silentSignIn(mGoogleApiClient);
            if (opr.isDone()) {
                // If the user's cached credentials are valid, the OptionalPendingResult will be "done"
                // and the GoogleSignInResult will be available instantly.
                Log.d(TAG, "Got cached sign-in");
                GoogleSignInResult result = opr.get();
                handleSignInResult(result);
            } else {
                // If the user has not previously signed in on this device or the sign-in has expired,
                // this asynchronous branch will attempt to sign in the user silently.  Cross-device
                // single sign-on will occur in this branch.
                showProgressDialog();
                opr.setResultCallback(new ResultCallback<GoogleSignInResult>() {
                    @Override
                    public void onResult(GoogleSignInResult googleSignInResult) {
                        hideProgressDialog();
                        handleSignInResult(googleSignInResult);
                    }
                });
            }
        }

        @Override
        public void onConnectionFailed(@NonNull ConnectionResult connectionResult) {
            // An unresolvable error has occurred and Google APIs (including Sign-In) will not
            // be available.
            Log.d(TAG, "onConnectionFailed:" + connectionResult);
        }

        private void showProgressDialog() {
            if (mProgressDialog == null) {
                mProgressDialog = new ProgressDialog(this);
                mProgressDialog.setMessage("loading");
                mProgressDialog.setIndeterminate(true);
            }

            mProgressDialog.show();
        }

        private void hideProgressDialog() {
            if (mProgressDialog != null && mProgressDialog.isShowing()) {
                mProgressDialog.hide();
            }
        }

        private void updateUI(boolean isSignedIn) {
            if (isSignedIn) {
                btnSignIn.setVisibility(View.GONE);
               Intent i = new Intent(Login.this,Signin.class);
              startActivity(i);
            } else {
                btnSignIn.setVisibility(View.VISIBLE);
                btnSignOut.setVisibility(View.GONE);
                btnRevokeAccess.setVisibility(View.GONE);
                llProfileLayout.setVisibility(View.GONE);
            }
        }
}

它的xml代码是：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/main_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:weightSum="4">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="2"
        android:gravity="center_horizontal"
        android:orientation="vertical">


    </LinearLayout>


    <RelativeLayout
        android:layout_width="fill_parent"
        android:layout_height="0dp"
        android:layout_weight="2">

        <com.google.android.gms.common.SignInButton
            android:id="@+id/sign_in_button"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:visibility="visible"
            tools:visibility="gone" />




    </RelativeLayout>

</LinearLayout>

我的LogCat是：

 at com.google.android.gms.auth.api.Auth$4.zza(Unknown Source)
   at com.google.android.gms.common.api.GoogleApiClient$Builder.zza(Unknown Source)
   at com.google.android.gms.common.api.GoogleApiClient$Builder.zzuQ(Unknown Source)
   at com.google.android.gms.common.api.GoogleApiClient$Builder.build(Unknown Source)
   at com.example.hp_pc.earnmebucks.Login.onCreate(Login.java:67)
   at android.app.Activity.performCreate(Activity.java:6001)
   at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1105)
   at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2261)
   at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2368)
   at android.app.ActivityThread.access$800(ActivityThread.java:144)
   at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1285)
   at android.os.Handler.dispatchMessage(Handler.java:102)
   at android.os.Looper.loop(Looper.java:135)
   at android.app.ActivityThread.main(ActivityThread.java:5233)
   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:898)
   at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:693)

请帮忙。我的应用程序在启动活动后崩溃。如果有人能帮助我，我将非常感激。我无法知道空指针异常在哪里。提前谢谢。

Answer 1

问题在于

    Thread timerThread = new Thread() {
        public void run() {
            try {
                sleep(3000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            } finally {
                Intent intent = new Intent(SplashActivity.this, Login.class);
                startActivity(intent);
            }
        }
    };
    timerThread.start();

你不能从非UI线程开始意图。使用runOnUiThread

所以你的代码应该是

        Thread timerThread = new Thread() {
            public void run() {
                try {
                    sleep(3000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                } finally {
                    runOnUiThread(new Runnable() {
                        @Override
                        public void run() {
                            Intent intent = new Intent(SplashActivity.this, Login.class);
                            SplashActivity.this.startActivity(intent);
                        }
                    });
                }
            }
        };
        timerThread.start();

另外，您可以使用CountDownTimer

简化它

new CountDownTimer(3000, 1000) {

    public void onTick(long millisUntilFinished) {
    }
    public void onFinish() {
       Intent intent = new Intent(SplashActivity.this, Login.class);
       startActivity(intent);
    }

}.start();

Answer 2

试试这个： -

 new Handler().postDelayed(new Runnable() {

        @Override
        public void run() {
            // TODO Auto-generated method stub
            Intent i = new Intent(getApplicationContext(), Login.class);
            startActivity(i);
            finish();
        }
    }, 1000);

Answer 3

compile＆＃39; com.google.android.gms：play-services-auth：10.2.1＆＃39;

//添加到文件的底部申请插件：＆＃39; com.google.gms.google-services＆＃39;

在build.gradle sync中添加后再运行。

我的应用程序崩溃了

3 个答案: