Android应用程序在运行时崩溃：'；java.lang.String android.content.Context.getPackageName（）'；
我想知道是否有人能帮忙。每次我运行android应用程序项目时，它都会崩溃。我已经把它缩小到一个单一的功能，但我不知道为什么它会崩溃 错误：Android应用程序在运行时崩溃：'；java.lang.String android.content.Context.getPackageName（）'；,java,android,Java,Android,我想知道是否有人能帮忙。每次我运行android应用程序项目时，它都会崩溃。我已经把它缩小到一个单一的功能，但我不知道为什么它会崩溃 错误： 05-07 17:38:22.059 3952-3986/com.tfs.appname W/System: ClassLoader referenced unknown path: /data/data/com.tfs.appname/lib 05-07 17:38:22.122 3952-3952/com.tfs.appname D/A
05-07 17:38:22.059 3952-3986/com.tfs.appname W/System: ClassLoader referenced unknown path: /data/data/com.tfs.appname/lib
05-07 17:38:22.122 3952-3952/com.tfs.appname D/AndroidRuntime: Shutting down VM
05-07 17:38:22.123 3952-3952/com.tfs.appname E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.tfs.appname, PID: 3952
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.tfs.appname/com.tfs.appname.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String android.content.Context.getPackageName()' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2416)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:4077)
at android.app.ActivityThread.-wrap15(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1350)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String android.content.Context.getPackageName()' on a null object reference
at android.content.ContextWrapper.getPackageName(ContextWrapper.java:133)
at android.app.Activity.getLocalClassName(Activity.java:5205)
at android.app.Activity.getPreferences(Activity.java:5239)
at com.tfs.appname.helpers.isLoggedIn(helpers.java:99)
at com.tfs.appname.MainActivity$override.onCreate(MainActivity.java:35)
at com.tfs.appname.MainActivity$override.access$dispatch(MainActivity.java)
at com.tfs.appname.MainActivity.onCreate(MainActivity.java:0)
at android.app.Activity.performCreate(Activity.java:6237)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1107)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2369)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:4077)
at android.app.ActivityThread.-wrap15(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1350)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
05-07 17:38:30.716 3952-3952/com.tfs.appname I/Process: Sending signal. PID: 3952 SIG: 9
package com.tfs.appname;
import android.content.Intent;
import android.net.Uri;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import com.google.android.gms.appindexing.Action;
import com.google.android.gms.appindexing.AppIndex;
import com.google.android.gms.common.api.GoogleApiClient;
public class MainActivity extends AppCompatActivity {
/**
* ATTENTION: This was auto-generated to implement the App Indexing API.
* See https://g.co/AppIndexing/AndroidStudio for more information.
*/
private GoogleApiClient client;
Button LoginButton, RegisterButton;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
final helpers helpers = new helpers();
client = new GoogleApiClient.Builder(this).addApi(AppIndex.API).build();
Button LoginButton = (Button) findViewById(R.id.button_login);
Button RegisterButton = (Button) findViewById(R.id.button_register);
if (helpers.isLoggedIn()) {
startActivity(new Intent(MainActivity.this, Dashboard.class));
}
RegisterButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
startActivity(new Intent(MainActivity.this, Register.class));
}
});
LoginButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
startActivity(new Intent(MainActivity.this, Login.class));
}
});
}
@Override
public void onStart() {
super.onStart();
// ATTENTION: This was auto-generated to implement the App Indexing API.
// See https://g.co/AppIndexing/AndroidStudio for more information.
client.connect();
Action viewAction = Action.newAction(
Action.TYPE_VIEW, // TODO: choose an action type.
"Main Page", // TODO: Define a title for the content shown.
// TODO: If you have web page content that matches this app activity's content,
// make sure this auto-generated web page URL is correct.
// Otherwise, set the URL to null.
Uri.parse("http://host/path"),
// TODO: Make sure this auto-generated app URL is correct.
Uri.parse("android-app://com.tfs.appname/http/host/path")
);
AppIndex.AppIndexApi.start(client, viewAction);
}
@Override
public void onStop() {
super.onStop();
// ATTENTION: This was auto-generated to implement the App Indexing API.
// See https://g.co/AppIndexing/AndroidStudio for more information.
Action viewAction = Action.newAction(
Action.TYPE_VIEW, // TODO: choose an action type.
"Main Page", // TODO: Define a title for the content shown.
// TODO: If you have web page content that matches this app activity's content,
// make sure this auto-generated web page URL is correct.
// Otherwise, set the URL to null.
Uri.parse("http://host/path"),
// TODO: Make sure this auto-generated app URL is correct.
Uri.parse("android-app://com.tfs.appname/http/host/path")
);
AppIndex.AppIndexApi.end(client, viewAction);
client.disconnect();
}
}
package com.tfs.appname;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.net.Uri;
import android.os.Bundle;
import android.preference.PreferenceManager;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
import com.google.android.gms.appindexing.Action;
import com.google.android.gms.appindexing.AppIndex;
import com.google.android.gms.common.api.GoogleApiClient;
import com.kosalgeek.asynctask.AsyncResponse;
import com.kosalgeek.asynctask.PostResponseAsyncTask;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.HashMap;
import static android.app.PendingIntent.getActivity;
public class Login extends AppCompatActivity implements AsyncResponse {
Button LoginSubmitButton, LoginRegisterButton;
EditText LoginEmail, LoginPassword;
/**
* ATTENTION: This was auto-generated to implement the App Indexing API.
* See https://g.co/AppIndexing/AndroidStudio for more information.
*/
private GoogleApiClient client;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
final helpers helpers = new helpers();
final EditText LoginEmail = (EditText) findViewById(R.id.login_email);
final EditText LoginPassword = (EditText) findViewById(R.id.login_password);
Button LoginSubmitButton = (Button) findViewById(R.id.login_submit);
Button LoginRegisterButton = (Button) findViewById(R.id.login_register_button);
LoginRegisterButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
startActivity(new Intent(Login.this, Register.class));
}
});
assert LoginSubmitButton != null;
LoginSubmitButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
final Context context = getApplicationContext();
int duration = Toast.LENGTH_SHORT;
if (helpers.isEmpty(LoginEmail)) {
CharSequence text = "Please enter your email address.";
Toast toast = Toast.makeText(context, text, duration);
toast.show();
} else {
if (helpers.isEmpty(LoginPassword)) {
CharSequence text = "Please enter your password.";
Toast toast = Toast.makeText(context, text, duration);
toast.show();
} else {
if (helpers.isValidEmail(LoginEmail))
if (helpers.isValidPassword(LoginPassword)) {
HashMap<String, String> postData = new HashMap<String, String>();
postData.put("emailaddress", LoginEmail.getText().toString());
postData.put("password", LoginPassword.getText().toString());
final PostResponseAsyncTask loginTask = new PostResponseAsyncTask(Login.this, postData, new AsyncResponse() {
@Override
public void processFinish(String s) {
JSONObject results = null;
String result_status = null;
String MID = null;
String MT = null;
try {
results = new JSONObject(s);
result_status = results.getString("STATUS");
MID = results.getString("MID");
MT = results.getString("MT");
} catch (JSONException e) {
e.printStackTrace();
}
if (result_status.equalsIgnoreCase("success")) {
SharedPreferences sharedPref = Login.this.getPreferences(Context.MODE_PRIVATE);
SharedPreferences.Editor editor = sharedPref.edit();
editor.putString("MID", MID);
editor.putString("MTOK", MT);
editor.commit();
startActivity(new Intent(Login.this, Dashboard.class));
} else {
Context context = getApplicationContext();
int duration = Toast.LENGTH_SHORT;
CharSequence text = result_status;
Toast toast = Toast.makeText(context, text, duration);
toast.show();
}
}
});
loginTask.execute("http://192.168.1.64/app/test.php");
} else {
CharSequence text = "Invalid password.";
Toast toast = Toast.makeText(context, text, duration);
toast.show();
}
else {
CharSequence text = "Invalid email address.";
Toast toast = Toast.makeText(context, text, duration);
toast.show();
}
}
}
}
});
// ATTENTION: This was auto-generated to implement the App Indexing API.
// See https://g.co/AppIndexing/AndroidStudio for more information.
client = new GoogleApiClient.Builder(this).addApi(AppIndex.API).build();
}
@Override
public void processFinish(String s) {
}
@Override
public void onStart() {
super.onStart();
// ATTENTION: This was auto-generated to implement the App Indexing API.
// See https://g.co/AppIndexing/AndroidStudio for more information.
client.connect();
Action viewAction = Action.newAction(
Action.TYPE_VIEW, // TODO: choose an action type.
"Login Page", // TODO: Define a title for the content shown.
// TODO: If you have web page content that matches this app activity's content,
// make sure this auto-generated web page URL is correct.
// Otherwise, set the URL to null.
Uri.parse("http://host/path"),
// TODO: Make sure this auto-generated app URL is correct.
Uri.parse("android-app://com.tfs.appname/http/host/path")
);
AppIndex.AppIndexApi.start(client, viewAction);
}
@Override
public void onStop() {
super.onStop();
// ATTENTION: This was auto-generated to implement the App Indexing API.
// See https://g.co/AppIndexing/AndroidStudio for more information.
Action viewAction = Action.newAction(
Action.TYPE_VIEW, // TODO: choose an action type.
"Login Page", // TODO: Define a title for the content shown.
// TODO: If you have web page content that matches this app activity's content,
// make sure this auto-generated web page URL is correct.
// Otherwise, set the URL to null.
Uri.parse("http://host/path"),
// TODO: Make sure this auto-generated app URL is correct.
Uri.parse("android-app://com.tfs.appname/http/host/path")
);
AppIndex.AppIndexApi.end(client, viewAction);
client.disconnect();
}
}
package com.tfs.appname；
导入android.content.Context；
导入android.content.Intent；
导入android.content.SharedReferences；
导入android.net.Uri；
导入android.os.Bundle；
导入android.preference.PreferenceManager；
导入android.support.v7.app.AppActivity；
导入android.view.view；
导入android.widget.Button；
导入android.widget.EditText；
导入android.widget.Toast；
导入com.google.android.gms.appindexing.Action；
导入com.google.android.gms.AppIndex.AppIndex；
导入com.google.android.gms.common.api.GoogleAppClient；
导入com.kosalgeek.asynctask.AsyncResponse；
导入com.kosalgeek.asynctask.PostResponseAsyncTask；
导入org.json.JSONException；
导入org.json.JSONObject；
导入java.util.HashMap；
导入静态android.app.pendingent.getActivity；
公共类登录扩展AppCompatActivity实现异步响应{
按钮LoginSubmitButton、LoginRegisterButton；
编辑文本登录邮件，登录密码；
/**
*注意：这是自动生成的，用于实现应用程序索引API。
*看https://g.co/AppIndexing/AndroidStudio 了解更多信息。
*/
私人谷歌客户；
@凌驾
创建时受保护的void（Bundle savedInstanceState）{
super.onCreate（savedInstanceState）；
setContentView（R.layout.activity\u登录）；
最终助手助手=新助手（）；
最终EditText LoginEmail=（EditText）findViewById（R.id.login\u电子邮件）；
最终EditText登录密码=（EditText）findViewById（R.id.login\u密码）；
按钮登录SubmitButton=（按钮）findViewById（R.id.login\u submit）；
按钮LoginRegisterButton=（按钮）findViewById（R.id.login\u register\u按钮）；
LoginRegisterButton.setOnClickListener（新视图.OnClickListener（）{
@凌驾
公共void onClick（视图）{
startActivity（新意图（Login.this、Register.class））；
}
});
assert LoginSubmitButton！=null；
LoginSubmitButton.setOnClickListener（新视图.OnClickListener（））{
@凌驾
公共void onClick（视图）{
最终上下文=getApplicationContext（）；
int duration=Toast.LENGTH\u SHORT；
if（helpers.isEmpty（LoginEmail））{
CharSequence text=“请输入您的电子邮件地址。”；
Toast Toast=Toast.makeText（上下文、文本、持续时间）；
toast.show（）；
}否则{
if（helpers.isEmpty（LoginPassword））{
CharSequence text=“请输入您的密码。”；
Toast Toast=Toast.makeText（上下文、文本、持续时间）；
toast.show（）；
}否则{
if（helpers.isValidEmail（LoginEmail））
if（helpers.isValidPassword（LoginPassword））{
HashMap postData=新HashMap（）；
postData.put（“emailaddress”，LoginEmail.getText（）.toString（））；
postData.put（“密码”，LoginPassword.getText（）.toString（））；
final PostResponseAsyncTask loginTask=新的PostResponseAsyncTask（Login.this，postData，new AsyncResponse（））{
@凌驾
公共void processFinish（字符串s）{
JSONObject results=null；
字符串结果\u状态=空；
字符串MID=null；
字符串MT=null；
试一试{
结果=新的JSONObject；
result_status=results.getString（“status”）；
MID=results.getString（“MID”）；
MT=results.getString（“MT”）；
}捕获（JSONException e）{
e、 printStackTrace（）；
}
if（结果\状态相等信号案例（“成功”））{
SharedPreferences sharedPref=Login.this.getPreferences（Context.MODE\u PRIVATE）；
SharedPreferences.Editor=sharedPref.edit（）；
编辑器.putString（“MID”，MID）；
编辑器.putString（“MTOK”，MT）；
commit（）；
startActivity（新意图（Login.this、Dashboard.class））；
}否则{
Context=getApplicationContext（）；
int duration=Toast.LENGTH\u SHORT；
CharSequence text=结果\状态；
Toast Toast=Toast.makeText（上下文、文本、持续时间）；
toast.show（）；
}
}
});
loginTask.execute（“http://192.168.1.64/app/test.php");
}否则{
CharSequence text=“密码无效。”；
Toast Toast=Toast.makeText（con
package com.tfs.appname;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.net.Uri;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.text.TextUtils;
import android.util.Patterns;
import android.widget.EditText;
import android.widget.Toast;
import com.google.android.gms.appindexing.Action;
import com.google.android.gms.appindexing.AppIndex;
import com.google.android.gms.common.api.GoogleApiClient;
import com.kosalgeek.asynctask.AsyncResponse;
import com.kosalgeek.asynctask.PostResponseAsyncTask;
import org.json.JSONException;
import org.json.JSONObject;
import java.io.BufferedInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.net.URLConnection;
import java.util.HashMap;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/**
* Created by Offic on 03/05/2016.
*/
public class helpers extends AppCompatActivity implements AsyncResponse {
/**
* ATTENTION: This was auto-generated to implement the App Indexing API.
* See https://g.co/AppIndexing/AndroidStudio for more information.
*/
private GoogleApiClient client;
boolean isEmpty(EditText etText) {
return etText.getText().toString().trim().length() <= 0;
}
public boolean isValidEmail(EditText email) {
if (TextUtils.isEmpty(email.getText())) {
return false;
} else {
return Patterns.EMAIL_ADDRESS.matcher(email.getText()).matches();
}
}
public boolean isValidPassword(EditText password) {
String regExpn = "^[a-z0-9_]{6,24}$";
CharSequence inputStr = password.getText();
Pattern pattern = Pattern.compile(regExpn, Pattern.CASE_INSENSITIVE);
Matcher matcher = pattern.matcher(inputStr);
if (matcher.matches()) {
return true;
} else {
return false;
}
}
private boolean verifySession(String MID, String MTOK) {
HashMap<String, String> postData = new HashMap<String, String>();
postData.put("MID", MID);
postData.put("MTOK", MTOK);
final Boolean[] Ret = {false};
final PostResponseAsyncTask loginTask = new PostResponseAsyncTask(this, postData, new AsyncResponse() {
@Override
public void processFinish(String s) {
JSONObject results = null;
String result_status = null;
try {
results = new JSONObject(s);
result_status = results.getString("STATUS");
} catch (JSONException e) {
e.printStackTrace();
}
if (result_status == "success") {
Ret[0] = true;
} else {
Ret[0] = false;
}
}
});
loginTask.execute("http://192.168.1.64/app/test.php");
return Ret[0];
}
public boolean isLoggedIn() {
SharedPreferences sharedPref = this.getPreferences(Context.MODE_PRIVATE);
String MID = sharedPref.getString("MID", null);
String MT = sharedPref.getString("MTOK", null);
if (MID == null || MT == null) {
return false;
} else {
return verifySession(MID, MT);
}
}
@Override
public void processFinish(String s) {
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
client = new GoogleApiClient.Builder(this).addApi(AppIndex.API).build();
}
@Override
public void onStart() {
super.onStart();
client.connect();
Action viewAction = Action.newAction(
Action.TYPE_VIEW, // TODO: choose an action type.
"helpers Page", // TODO: Define a title for the content shown.
Uri.parse("http://host/path"),
Uri.parse("android-app://com.tfs.appname/http/host/path")
);
AppIndex.AppIndexApi.start(client, viewAction);
}
@Override
public void onStop() {
super.onStop();
Action viewAction = Action.newAction(
Action.TYPE_VIEW, // TODO: choose an action type.
"helpers Page", // TODO: Define a title for the content shown.
// TODO: If you have web page content that matches this app activity's content,
// make sure this auto-generated web page URL is correct.
// Otherwise, set the URL to null.
Uri.parse("http://host/path"),
// TODO: Make sure this auto-generated app URL is correct.
Uri.parse("android-app://com.tfs.appname/http/host/path")
);
AppIndex.AppIndexApi.end(client, viewAction);
client.disconnect();
}
}
final helpers helpers = new helpers();
SharedPreferences sharedPref = this.getPreferences(Context.MODE_PRIVATE);