无法启动活动Android模拟器

时间:2016-04-30 09:49:00

标签: java android android-layout android-emulator

我是Android编程的新手。我正在关注Android开发者指南以开始使用Android。 尝试在模拟器上运行简单的Formular时,模拟器显示

  

“不幸的是,我的第一个应用程序停止了。”,

其中MyFormular是应用程序的名称。问题是我从布局资源文件中创建了新布局,并尝试连接到新的loyout fror here

setContentView(R.layout.form_layout (the new layout is form_layout)

新布局

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal" android:layout_width="match_parent"
android:layout_height="match_parent">

<RelativeLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_weight="5">

    <EditText
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceLarge"
        android:text="Please submit your details"
        android:id="@+id/textView"
        android:layout_alignParentTop="true"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_marginTop="46dp" />

    <EditText
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:inputType="textPersonName"
        android:text="Name"
        android:ems="10"
        android:id="@+id/editText"
        android:layout_marginTop="46dp"
        android:layout_below="@+id/textView"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:hint="Name" />

    <EditText
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:inputType="textEmailAddress"
        android:ems="10"
        android:id="@+id/editText2"
        android:layout_centerVertical="true"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_marginTop="46dp"
        android:hint="Email" />

    <EditText
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:inputType="textPassword"
        android:ems="10"
        android:id="@+id/editText3"
        android:layout_below="@+id/editText2"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_marginTop="46dp"
        android:hint="Password" />

    <EditText
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:inputType="textPassword"
        android:ems="10"
        android:id="@+id/editText4"
        android:layout_below="@+id/editText3"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_marginTop="46dp"
        android:hint="Confirm Password" />
</RelativeLayout>

<RelativeLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_weight="5">

    <ImageView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/imageView"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="36dp"
        android:src="@mipmap/ic_launcher" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceLarge"
        android:text="Terms &amp; Conditions"
        android:id="@+id/textView2"
        android:layout_below="@+id/imageView"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="46dp" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:attr/textAppearanceSmall"
        android:text="A Terms and Conditions can be used for both your "
        android:id="@+id/textView3"
        android:layout_centerVertical="true"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="10dp" />

    <CheckBox
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="I agree"
        android:id="@+id/checkBox"
        android:layout_alignParentBottom="true"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_marginLeft="38dp"
        android:layout_marginStart="38dp"
        android:layout_marginBottom="38dp"
        android:checked="false"
        android:layout_marginRight="46dp" />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Can&apos;t wait!Sign me up!"
        android:id="@+id/button"
        android:layout_alignTop="@+id/checkBox"
        android:layout_alignParentRight="true"
        android:layout_alignParentEnd="true"
        android:layout_marginRight="85dp"
        android:layout_marginEnd="75dp" />
</RelativeLayout>
</LinearLayout>

MainFormular.java

    package com.example.melisa.myformular;

     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;

     public class MainFormular extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.form_layout);
        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_formular, 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);
    }


 }

在android.app.Activity.performCreate(activity_main_formular

 <?xml version="1.0" encoding="utf-8"?>

<android.support.design.widget.AppBarLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:theme="@style/AppTheme.AppBarOverlay">

    <android.support.v7.widget.Toolbar
        android:id="@+id/toolbar"
        android:layout_width="match_parent"
        android:layout_height="?attr/actionBarSize"
        android:background="?attr/colorPrimary"
        app:popupTheme="@style/AppTheme.PopupOverlay" />

</android.support.design.widget.AppBarLayout>

<include layout="@layout/content_main_formular" />

<android.support.design.widget.FloatingActionButton
    android:id="@+id/fab"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="bottom|end"
    android:layout_margin="@dimen/fab_margin"
    android:src="@android:drawable/ic_dialog_email" />

  </android.support.design.widget.CoordinatorLayout>

logcat的

日志是,

  

04-30 09:13:11.176 10175-10175 / com.example.melisa.myformular I / Process:发送信号。 PID:10175 SIG:9   04-30 10:03:45.336 10427-10427 / com.example.melisa.myformular W / System:ClassLoader引用未知路径:/data/app/com.example.melisa.myformular-1/lib/x86   04-30 10:03:47.008 10427-10427 / com.example.melisa.myformular W / System:ClassLoader引用未知路径:/data/app/com.example.melisa.myformular-1/lib/x86   04-30 10:03:47.112 10427-10427 / com.example.melisa.myformular W / art:在Android 4.1之前,方法android.graphics.PorterDuffColorFilter android.support.graphics.drawable.VectorDrawableCompat.updateTintFilter(android.graphics.PorterDuffColorFilter ,android.content.res.ColorStateList,android.graphics.PorterDuff $ Mode)会错误地覆盖android.graphics.drawable.Drawable中的package-private方法   04-30 10:03:47.128 10427-10427 / com.example.melisa.myformular D / AndroidRuntime:关闭虚拟机

     

04-30 10:03:47.128 10427-10427 / com.example.melisa.myformular E / AndroidRuntime:FATAL EXCEPTION:main   过程:com.example.melisa.myformular,PID:10427   java.lang.RuntimeException:无法启动活动ComponentInfo {com.example.melisa.myformular / com.example.melisa.myformular.MainFormular}:java.lang.NullPointerException:尝试调用虚方法'void android.support.design。在null对象引用上的widget.FloatingActionButton.setOnClickListener(android.view.View $ OnClickListener)'      在android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2416)      在android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)      在android.app.ActivityThread.-wrap11(ActivityThread.java)      在android.app.ActivityThread $ H.handleMessage(ActivityThread.java:1344)      在android.os.Handler.dispatchMessage(Handler.java:102)      在android.os.Looper.loop(Looper.java:148)      在android.app.ActivityThread.main(ActivityThread.java:5417)      at java.lang.reflect.Method.invoke(Native Method)      在com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run(ZygoteInit.java:726)      在com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)   引起:java.lang.NullPointerException:尝试在空对象引用上调用虚方法'void android.support.design.widget.FloatingActionButton.setOnClickListener(android.view.View $ OnClickListener)'      在com.example.melisa.myformular.MainFormular.onCreate(MainFormular.java:22)      在android.app.Activity.performCreate(Activity.java:6237)      在android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1107)      在android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2369)      在android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)      在android.app.ActivityThread.-wrap11(ActivityThread.java)      在android.app.ActivityThread $ H.handleMessage(ActivityThread.java:1344)      在android.os.Handler.dispatchMessage(Handler.java:102)      在android.os.Looper.loop(Looper.java:148)      在android.app.ActivityThread.main(ActivityThread.java:5417)      at java.lang.reflect.Method.invoke(Native Method)      在com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run(ZygoteInit.java:726)      在com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)

1 个答案:

答案 0 :(得分:0)

请删除此代码并尝试运行您的应用......

在你的布局中,FloatingActionButton视图不存在,你正试图绑定并点击事件......

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();
            }
        });

这也是......

@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_formular, menu);
        return true;
    }

享受编码......