android 设备异常,尝试在android studio上运行设备时出现NullPointer异常

我是

android studio的新手.我在

Android studio上运行设备时遇到Nullpointer异常.我正在使用armeabi-v7a sdk作为手臂处理器.错误看起来像这样..

null

java.lang.NullPointerException

at com.android.tools.idea.run.AndroidSessionInfo.isEmbeddable(AndroidSessionInfo.java:62)

at com.android.tools.idea.run.AndroidRunConfigurationBase.getOldSessionTarget(AndroidRunConfigurationBase.java:307)

at com.android.tools.idea.run.AndroidRunConfigurationBase.getState(AndroidRunConfigurationBase.java:279)

at com.intellij.execution.runners.ExecutionEnvironment.getState(ExecutionEnvironment.java:201)

at com.intellij.execution.runners.BaseProgramRunner.execute(BaseProgramRunner.java:58)

at com.intellij.execution.runners.GenericProgramRunner.execute(GenericProgramRunner.java:31)

at com.intellij.execution.runners.BaseProgramRunner.execute(BaseProgramRunner.java:53)

at com.intellij.execution.runners.GenericProgramRunner.execute(GenericProgramRunner.java:31)

at com.intellij.execution.ProgramRunnerUtil.executeConfiguration(ProgramRunnerUtil.java:94)

at com.intellij.execution.impl.ExecutionManagerImpl.start(ExecutionManagerImpl.java:396)

at com.intellij.execution.impl.ExecutionManagerImpl.access$400(ExecutionManagerImpl.java:61)

at com.intellij.execution.impl.ExecutionManagerImpl$5.run(ExecutionManagerImpl.java:384)

at com.intellij.util.concurrency.QueueProcessor.runSafely(QueueProcessor.java:238)

at com.intellij.util.Alarm$Request$1.run(Alarm.java:351)

at com.intellij.openapi.application.impl.LaterInvocator$FlushQueue.run(LaterInvocator.java:332)

at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:311)

at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:756)

at java.awt.EventQueue.access$500(EventQueue.java:97)

at java.awt.EventQueue$3.run(EventQueue.java:709)

at java.awt.EventQueue$3.run(EventQueue.java:703)

at java.security.AccessController.doPrivileged(Native Method)

at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)

at java.awt.EventQueue.dispatchEvent(EventQueue.java:726)

at com.intellij.ide.IdeEventQueue.defaultDispatchEvent(IdeEventQueue.java:734)

at com.intellij.ide.IdeEventQueue._dispatchEvent(IdeEventQueue.java:569)

at com.intellij.ide.IdeEventQueue.dispatchEvent(IdeEventQueue.java:382)

at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)

at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)

at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)

at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)

at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)

at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)

表现：

package="com.example.de34.myfirstapp">

android:allowBackup="true"

android:icon="@mipmap/ic_launcher"

android:label="@string/app_name"

android:supportsRtl="true"

android:theme="@style/AppTheme">

android:name=".MainActivity"

android:label="@string/app_name"

android:theme="@style/AppTheme.NoActionBar">

我的gradle看起来像：

apply plugin: 'com.android.application'

android {

compileSdkVersion 23

buildToolsVersion "23.0.1"

defaultConfig {

applicationId "com.example.de34.myfirstapp"

minSdkVersion 15

targetSdkVersion 21

versionCode 1

versionName "1.0"

}

buildTypes {

release {

minifyEnabled false

proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'

}

}

}

dependencies {

compile fileTree(include: ['*.jar'], dir: 'libs')

//testCompile 'junit:junit:4.12'

compile 'com.android.support:appcompat-v7:23.1.1'

compile 'com.android.support:design:23.1.1'

}

主要活动节点：

package com.example.de34.myfirstapp;

import android.os.Bundle;

import android.support.design.widget.FloatingActionButton;

import android.support.design.widget.Snackbar;

import android.support.v7.app.AppCompatActivity;

import android.support.v7.widget.Toolbar;

import android.view.View;

import android.view.Menu;

import android.view.MenuItem;

import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);

setSupportActionBar(toolbar);

FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);

fab.setOnClickListener(new View.OnClickListener() {

@Override

public void onClick(View view) {

Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)

.setAction("Action", null).show();

}

});

}

@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_main, menu);

return true;

}

public void OnclickMe(View view){

Toast toast=Toast.makeText(this,"oh you clicked",Toast.LENGTH_LONG);

toast.show();

}

@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);

}

}

XML：

xmlns:app="http://schemas.android.com/apk/res-auto"

xmlns:tools="http://schemas.android.com/tools"

android:layout_width="match_parent"

android:layout_height="match_parent"

android:paddingBottom="@dimen/activity_vertical_margin"

android:paddingLeft="@dimen/activity_horizontal_margin"

android:paddingRight="@dimen/activity_horizontal_margin"

android:paddingTop="@dimen/activity_vertical_margin"

app:layout_behavior="@string/appbar_scrolling_view_behavior"

tools:context="com.example.de34.myfirstapp.MainActivity"

tools:showIn="@layout/activity_main">

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="Hello World!click me if you dare"

android:id="@+id/textView"

android:layout_alignParentTop="true"

android:layout_centerHorizontal="true" />

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="@string/clickMe"

android:id="@+id/button"

android:layout_marginTop="44dp"

android:layout_below="@+id/textView"

android:layout_centerHorizontal="true" />