Question

我试图打开按钮点击“类别活动”的活动正在打开但是学习活动没有打开。请我开展学习活动。提前谢谢

{
  //  Main Activity


import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;


public class MainActivity extends Activity {



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


    public void categories (View categories)
    {
        Intent intent = new Intent(this, Study.class);
        startActivity(intent);

    }

    public void study (View view)
    {
         Intent intent = new Intent(this, Study.class);
        startActivity(intent);

    }
}
}


 Main xml



<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
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"
tools:context="com.itcheeta.englishverformsmaster.MainActivity" >

<Button
            android:id="@+id/categories"
            android:layout_width="match_parent"
            android:layout_height="50dp"
            android:text="Categories"
           android:onClick="categories" />

<Button
    android:id="@+id/study"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_below="@+id/categories"
    android:layout_centerHorizontal="true"
    android:layout_marginTop="52dp"
    android:text="study"
    android:onClick="study" />

学习活动

import android.app.Activity;
import android.os.Bundle;
import android.widget.ScrollView;

public class Study extends Activity {
    private ScrollView layMain;
    private TableGenerator mTable;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_study);
        showTable();
    }

    private void showTable() {
        mTable = new TableGenerator(getApplicationContext());
        layMain = (ScrollView)findViewById(R.id.table);

        String[] firstRow = {"Present", "Past", "Future" };
        String[] secondRow = {"Do", "Did", "Done" };
        String[] thridRow = {"Come", "Came", "Come"};
        String[] fourthRow = {"Go", "Went", "Gone"};

        mTable.addRow(firstRow);
        mTable.addRow(secondRow);
        mTable.addRow(thridRow);
        mTable.addRow(fourthRow);

        layMain.removeAllViews();
        layMain.addView(mTable.getTable());
    }


}

研究xml

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

    <ScrollView
        android:id="@+id/table"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content" >
    </ScrollView>

</LinearLayout>

表生成器活动

import android.content.Context;
import android.view.Gravity;
import android.view.ViewGroup;
import android.widget.TableLayout;
import android.widget.TableRow;
import android.widget.TextView;


public class TableGenerator {
    private final Context mContext;
    private TableLayout mTable;

    private TableLayout.LayoutParams rowParams = new TableLayout.LayoutParams();
    private TableRow.LayoutParams colParams = new TableRow.LayoutParams();

    public TableGenerator(Context context) {
        mContext = context;
        mTable = new TableLayout(context);
        rowParams.setMargins(0, 0, 0, 1);
        colParams.setMargins(0, 0, 1, 0);

        TableLayout.LayoutParams lptable = new TableLayout.LayoutParams(
                ViewGroup.LayoutParams.MATCH_PARENT,
                ViewGroup.LayoutParams.MATCH_PARENT);
        mTable.setLayoutParams(lptable);

        mTable.setStretchAllColumns(true);
        mTable.setBackgroundColor(mContext.getResources().getColor(
                R.color.table_background));
    }

    public void addRow(String[] data) {
        TableRow tr = new TableRow(mContext);
        tr.setBackgroundColor(mContext.getResources().getColor(
                R.color.table_background));

        tr.setLayoutParams(rowParams);

        for (int iCol = 0; iCol < data.length; iCol++) {
            TextView tvCol = new TextView(mContext);
            tvCol.setText(data[iCol]);
            tvCol.setGravity(Gravity.CENTER | Gravity.CENTER);
            tvCol.setPadding(3, 3, 3, 3);
            tvCol.setTextColor(mContext.getResources().getColor(
                    R.color.text_black));
            tvCol.setLayoutParams(colParams);
            tvCol.setBackgroundColor(mContext.getResources().getColor(
                R.color.row_background));
            tr.addView(tvCol);
        }

        mTable.addView(tr);
    }

    public TableLayout getTable() {
        return mTable;
    }
}

LogCat消息：

{
12-12 02:29:37.191: E/AndroidRuntime(24473): FATAL EXCEPTION: main
12-12 02:29:37.191: E/AndroidRuntime(24473): java.lang.IllegalStateException: Could not execute method of the activity
12-12 02:29:37.191: E/AndroidRuntime(24473):    at android.view.View$1.onClick(View.java:3617)
12-12 02:29:37.191: E/AndroidRuntime(24473):    at android.view.View.performClick(View.java:4222)
12-12 02:29:37.191: E/AndroidRuntime(24473):    at android.view.View$PerformClick.run(View.java:17620)
12-12 02:29:37.191: E/AndroidRuntime(24473):    at android.os.Handler.handleCallback(Handler.java:800)
12-12 02:29:37.191: E/AndroidRuntime(24473):    at android.os.Handler.dispatchMessage(Handler.java:100)
12-12 02:29:37.191: E/AndroidRuntime(24473):    at android.os.Looper.loop(Looper.java:194)
12-12 02:29:37.191: E/AndroidRuntime(24473):    at android.app.ActivityThread.main(ActivityThread.java:5391)
12-12 02:29:37.191: E/AndroidRuntime(24473):    at java.lang.reflect.Method.invokeNative(Native Method)
12-12 02:29:37.191: E/AndroidRuntime(24473):    at java.lang.reflect.Method.invoke(Method.java:525)
12-12 02:29:37.191: E/AndroidRuntime(24473):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:833)
12-12 02:29:37.191: E/AndroidRuntime(24473):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:600)
12-12 02:29:37.191: E/AndroidRuntime(24473):    at dalvik.system.NativeStart.main(Native Method)
12-12 02:29:37.191: E/AndroidRuntime(24473): Caused by: java.lang.reflect.InvocationTargetException
12-12 02:29:37.191: E/AndroidRuntime(24473):    at java.lang.reflect.Method.invokeNative(Native Method)
12-12 02:29:37.191: E/AndroidRuntime(24473):    at java.lang.reflect.Method.invoke(Method.java:525)
12-12 02:29:37.191: E/AndroidRuntime(24473):    at android.view.View$1.onClick(View.java:3612)
12-12 02:29:37.191: E/AndroidRuntime(24473):    ... 11 more
12-12 02:29:37.191: E/AndroidRuntime(24473): Caused by: android.content.ActivityNotFoundException: Unable to find explicit activity class {com.itcheeta.englishverformsmaster/com.itcheeta.englishverformsmaster.Study}; have you declared this activity in your AndroidManifest.xml?
12-12 02:29:37.191: E/AndroidRuntime(24473):    at android.app.Instrumentation.checkStartActivityResult(Instrumentation.java:1693)
12-12 02:29:37.191: E/AndroidRuntime(24473):    at android.app.Instrumentation.execStartActivity(Instrumentation.java:1492)
12-12 02:29:37.191: E/AndroidRuntime(24473):    at android.app.Activity.startActivityForResult(Activity.java:3388)
12-12 02:29:37.191: E/AndroidRuntime(24473):    at android.app.Activity.startActivityForResult(Activity.java:3349)
12-12 02:29:37.191: E/AndroidRuntime(24473):    at android.app.Activity.startActivity(Activity.java:3584)
12-12 02:29:37.191: E/AndroidRuntime(24473):    at android.app.Activity.startActivity(Activity.java:3552)
12-12 02:29:37.191: E/AndroidRuntime(24473):    at com.itcheeta.englishverformsmaster.MainActivity.study(MainActivity.java:32)
}

Answer 1

您应该在AndroidManifest.xml文件中声明任何活动，然后才能启动它。在</application>添加此内容之前：

<activity android:name=".Study"/>

Answer 2

在Actvity内声明学习AndroidManifest.xml，您的LogCat消息指示异常：

引起：android.content。 ActivityNotFoundException ：无法找到显式活动类{com.itcheeta.englishverformsmaster / com.itcheeta.englishverformsmaster.Study}; 您是否在AndroidManifest.xml中声明了此活动？

示例：

 <activity      
            android:name=".Study"
            android:label="Study" >

某些Activity未打开：java.lang.IllegalStateException：无法执行活动的方法

2 个答案: