android - MainActivity.java 无法识别 activity_main.xml

Question

我为 android 练习制作了一个完美运行的计算器程序。我不喜欢我开始使用的相对布局，因此决定尝试网格布局。现在我的 MainActivity.java没有看到 activity_main.xml 文件。我检查了 R.java 文件并看到了 activity_main.xml 的列表，其中列出了所有按钮。 activity_main.xml 解析得很好。我试过重建程序无济于事。任何想法都会有所帮助!这是 activity_main.xml 文件

<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.GridLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:alignmentMode="alignBounds"
    android:columnCount="8"
    android:columnOrderPreserved="false"
    android:useDefaultMargins="true" >

    <EditText
        android:id="@+id/total"
        android:layout_column="0"
        android:layout_columnSpan="6"
        android:layout_gravity="left"
        android:layout_row="0"
        android:clickable="false"
        android:ems="10"
        android:inputType="none|number"
        android:textAlignment="textEnd"
        android:width="500dp" >

        <requestFocus />
    </EditText>

    <Button
        android:id="@+id/Button8"
        android:layout_column="1"
        android:layout_row="1"
        android:background="@drawable/button_light_grey"
        android:minHeight="40dip"
        android:minWidth="40dip"
        android:onClick="numberButtonEventHandler"
        android:text="8" />

    <Button
        android:id="@+id/Button9"
        android:layout_column="2"
        android:layout_row="1"
        android:background="@drawable/button_light_grey"
        android:minHeight="40dip"
        android:minWidth="40dip"
        android:onClick="numberButtonEventHandler"
        android:text="9" />

    <Button
        android:id="@+id/Button4"
        android:layout_column="0"
        android:layout_row="2"
        android:background="@drawable/button_light_grey"
        android:minHeight="40dip"
        android:minWidth="40dip"
        android:onClick="numberButtonEventHandler"
        android:text="4" />

    <Button
        android:id="@+id/Button5"
        android:layout_column="1"
        android:layout_row="2"
        android:background="@drawable/button_light_grey"
        android:minHeight="40dip"
        android:minWidth="40dip"
        android:onClick="numberButtonEventHandler"
        android:text="5" />

    <Button
        android:id="@+id/Button6"
        android:layout_column="2"
        android:layout_row="2"
        android:background="@drawable/button_light_grey"
        android:minHeight="40dip"
        android:minWidth="40dip"
        android:onClick="numberButtonEventHandler"
        android:text="6" />

    <Button
        android:id="@+id/ButtonMultiply"
        android:layout_column="3"
        android:layout_row="2"
        android:background="@drawable/custom_button"
        android:minHeight="40dip"
        android:minWidth="40dip"
        android:onClick="Multiply"
        android:text="*"
        android:textColor="@color/light_grey" />

    <Button
        android:id="@+id/Button1"
        android:layout_column="0"
        android:layout_row="3"
        android:background="@drawable/button_light_grey"
        android:minHeight="40dip"
        android:minWidth="40dip"
        android:onClick="numberButtonEventHandler"
        android:text="1" />

    <Button
        android:id="@+id/Button2"
        android:layout_column="1"
        android:layout_row="3"
        android:background="@drawable/button_light_grey"
        android:minHeight="40dip"
        android:minWidth="40dip"
        android:onClick="numberButtonEventHandler"
        android:text="2" />

    <Button
        android:id="@+id/Button3"
        android:layout_column="2"
        android:layout_row="3"
        android:background="@drawable/button_light_grey"
        android:minHeight="40dip"
        android:minWidth="40dip"
        android:onClick="numberButtonEventHandler"
        android:text="3" />

    <Button
        android:id="@+id/ButtonMinus"
        android:layout_column="3"
        android:layout_row="3"

        android:background="@drawable/custom_button"
        android:minHeight="40dip"
        android:minWidth="40dip"
        android:onClick="Subtract"
        android:text="-"
        android:textColor="@color/light_grey" />

    <Button
        android:id="@+id/ButtonDivide"
        android:layout_column="3"
        android:layout_gravity="right"
        android:layout_row="1"
        android:layout_rowSpan="2"
        android:background="@drawable/custom_button"
        android:minHeight="40dip"
        android:minWidth="40dip"
        android:onClick="Divide"
        android:text="/"
        android:textColor="@color/light_grey" />

    <Button
        android:id="@+id/button0"
        android:layout_column="0"
        android:layout_columnSpan="2"
        android:layout_row="4"
        android:background="@drawable/button_light_grey"
        android:minHeight="20dp"
        android:minWidth="82dp"
        android:onClick="numberButtonEventHandler"
        android:text="0" />

    <Button
        android:id="@+id/buttonPoint"
        android:layout_column="2"
        android:layout_row="4"
        android:background="@drawable/button_light_grey"
        android:minHeight="20dip"
        android:minWidth="40dp"
        android:onClick="numberButtonEventHandler"
        android:text="."
        android:width="20dip" />

    <Button
        android:id="@+id/ButtonPlus"
        android:layout_column="3"
        android:layout_row="4"
        android:background="@drawable/custom_button"
        android:minHeight="40dip"
        android:minWidth="40dip"
        android:onClick="Add"
        android:text="+"
        android:textColor="@color/light_grey" />

    <Button
        android:id="@+id/ButtonEqueals"
        android:layout_column="4"
        android:layout_row="3"
        android:layout_rowSpan="2"
        android:background="@drawable/custom_button"
        android:height="40dp"
        android:minHeight="82dp"
        android:minWidth="20dp"
        android:onClick="Equeals"
        android:text="="
        android:textColor="@color/light_grey"
        android:width="40dp" />

    <Button
        android:id="@+id/Button7"
        android:layout_column="0"
        android:layout_row="1"
        android:background="@drawable/button_light_grey"
        android:minHeight="40dip"
        android:minWidth="40dip"
        android:onClick="numberButtonEventHandler"
        android:text="7" />



</android.support.v4.widget.GridLayout>

这是 MainActivity.java 文件

package com.example.calculator;

import android.R;
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

public class MainActivity extends Activity{
    private String textTotal = "";
    Total total = new Total();
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main); <---here I get my first error
                                                    eclipse help suggests changing
        //setButtonListeners();                     to activity_list_item. This   
    }                                                   doesn't help

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

    public void numberButtonEventHandler(View v) {

        textTotal += ((Button) v).getText();
        TextView total = (TextView)findViewById(R.id.total);
        total.setText(textTotal);

    }

    public void Add(View v){

        try {
            total.doMath(Double.parseDouble(textTotal));
        } catch (NumberFormatException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        total.setOperater("+");
        TextView TextViewtotal = (TextView)findViewById(R.id.total);
        TextViewtotal.setText(Double.toString(total.getTotalValue()));
        textTotal = "";

    }

    public void Subtract(View v){
        try {
            total.doMath(Double.parseDouble(textTotal));
        } catch (NumberFormatException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        total.setOperater("-");
        TextView TextViewtotal = (TextView)findViewById(R.id.total);
        TextViewtotal.setText(Double.toString(total.getTotalValue()));
        textTotal = "";
    }

    public void Multiply(View v){
        try {
            total.doMath(Double.parseDouble(textTotal));
        } catch (NumberFormatException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        total.setOperater("*");
        TextView TextViewtotal = (TextView)findViewById(R.id.total);
        TextViewtotal.setText(Double.toString(total.getTotalValue()));
        textTotal = "";
    }

    public void Divide(View v){
        try {
            total.doMath(Double.parseDouble(textTotal));
        } catch (NumberFormatException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        total.setOperater("/");
        TextView TextViewtotal = (TextView)findViewById(R.id.total);
        TextViewtotal.setText(Double.toString(total.getTotalValue()));
        textTotal = "";
    }

    public void Equeals(View v){

        try {
            total.doMath(Double.parseDouble(textTotal));
        } catch (NumberFormatException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        total.setOperater("");
        TextView TextViewtotal = (TextView)findViewById(R.id.total);
        TextViewtotal.setText(Double.toString(total.getTotalValue()));
        textTotal = "";
    }



}

现在控制台输出:

[2013-04-03 22:19:26 - Calculator] Could not find Calculator.apk!
[2013-04-03 22:19:53 - Calculator] ------------------------------
[2013-04-03 22:19:53 - Calculator] Android Launch!
[2013-04-03 22:19:53 - Calculator] adb is running normally.
[2013-04-03 22:19:53 - Calculator] Could not find Calculator.apk!
[2013-04-03 22:20:58 - Calculator] ------------------------------
[2013-04-03 22:20:58 - Calculator] Android Launch!
[2013-04-03 22:20:58 - Calculator] adb is running normally.
[2013-04-03 22:20:58 - Calculator] Could not find Calculator.apk!
[2013-04-03 22:24:29 - Calculator] ------------------------------
[2013-04-03 22:24:29 - Calculator] Android Launch!
[2013-04-03 22:24:29 - Calculator] adb is running normally.
[2013-04-03 22:24:29 - Calculator] Could not find Calculator.apk!

下一个 logcat 输出:

04-03 22:46:16.121: E/AndroidRuntime(17973): FATAL EXCEPTION: main
04-03 22:46:16.121: E/AndroidRuntime(17973): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.calculator/com.example.calculator.MainActivity}: android.view.InflateException: Binary XML file line #2: Error inflating class android.support.v4.widget.GridLayout
04-03 22:46:16.121: E/AndroidRuntime(17973):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
04-03 22:46:16.121: E/AndroidRuntime(17973):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
04-03 22:46:16.121: E/AndroidRuntime(17973):    at android.app.ActivityThread.access$2300(ActivityThread.java:125)
04-03 22:46:16.121: E/AndroidRuntime(17973):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
04-03 22:46:16.121: E/AndroidRuntime(17973):    at android.os.Handler.dispatchMessage(Handler.java:99)
04-03 22:46:16.121: E/AndroidRuntime(17973):    at android.os.Looper.loop(Looper.java:123)
04-03 22:46:16.121: E/AndroidRuntime(17973):    at android.app.ActivityThread.main(ActivityThread.java:4627)
04-03 22:46:16.121: E/AndroidRuntime(17973):    at java.lang.reflect.Method.invokeNative(Native Method)
04-03 22:46:16.121: E/AndroidRuntime(17973):    at java.lang.reflect.Method.invoke(Method.java:521)
04-03 22:46:16.121: E/AndroidRuntime(17973):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:858)
04-03 22:46:16.121: E/AndroidRuntime(17973):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
04-03 22:46:16.121: E/AndroidRuntime(17973):    at dalvik.system.NativeStart.main(Native Method)
04-03 22:46:16.121: E/AndroidRuntime(17973): Caused by: android.view.InflateException: Binary XML file line #2: Error inflating class android.support.v4.widget.GridLayout
04-03 22:46:16.121: E/AndroidRuntime(17973):    at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:576)
04-03 22:46:16.121: E/AndroidRuntime(17973):    at android.view.LayoutInflater.inflate(LayoutInflater.java:385)
04-03 22:46:16.121: E/AndroidRuntime(17973):    at android.view.LayoutInflater.inflate(LayoutInflater.java:320)
04-03 22:46:16.121: E/AndroidRuntime(17973):    at android.view.LayoutInflater.inflate(LayoutInflater.java:276)
04-03 22:46:16.121: E/AndroidRuntime(17973):    at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:200)
04-03 22:46:16.121: E/AndroidRuntime(17973):    at android.app.Activity.setContentView(Activity.java:1647)
04-03 22:46:16.121: E/AndroidRuntime(17973):    at com.example.calculator.MainActivity.onCreate(MainActivity.java:17)
04-03 22:46:16.121: E/AndroidRuntime(17973):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1049)
04-03 22:46:16.121: E/AndroidRuntime(17973):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
04-03 22:46:16.121: E/AndroidRuntime(17973):    ... 11 more
04-03 22:46:16.121: E/AndroidRuntime(17973): Caused by: java.lang.ClassNotFoundException: android.support.v4.widget.GridLayout in loader dalvik.system.PathClassLoader[/data/app/com.example.calculator-1.apk]
04-03 22:46:16.121: E/AndroidRuntime(17973):    at dalvik.system.PathClassLoader.findClass(PathClassLoader.java:243)
04-03 22:46:16.121: E/AndroidRuntime(17973):    at java.lang.ClassLoader.loadClass(ClassLoader.java:573)
04-03 22:46:16.121: E/AndroidRuntime(17973):    at java.lang.ClassLoader.loadClass(ClassLoader.java:532)
04-03 22:46:16.121: E/AndroidRuntime(17973):    at android.view.LayoutInflater.createView(LayoutInflater.java:466)
04-03 22:46:16.121: E/AndroidRuntime(17973):    at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:565)
04-03 22:46:16.121: E/AndroidRuntime(17973):    ... 19 more

Answer 1

从 MainActivity.java 文件中的导入中删除 android.R。