Question

以下是带有日志猫说明我有错误的行的Java ...我会在该行添加注释...它说我已经将一个textview转换为按钮但是我没有所有

package k.t.m;

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

public class MainActivity extends Activity {

    TextView errors;
    TextView tkm;
    TextView result;
    TextView main;
    Button mainButton1;
    Button mainButton2;
    Button back;
    Button go;
    EditText textbox;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        main = (TextView) findViewById(R.id.main);
        back = (Button) findViewById(R.id.secondaryButtonBack);
        mainButton1  = (Button) findViewById(R.id.mainButton1);
        mainButton2  = (Button) findViewById(R.id.mainButton2);
        go = (Button) findViewById(R.id.goButton); // error here in the logcat... below

        tkm = (TextView) findViewById(R.id.mkm);
        result = (TextView) findViewById(R.id.result);
        errors = (TextView) findViewById(R.id.errors);
        textbox = (EditText) findViewById(R.id.TextBox);

        textbox.setVisibility(View.INVISIBLE);
        back.setVisibility(View.INVISIBLE);
        go.setVisibility(View.INVISIBLE);

       mainButton1.setOnClickListener(new OnClickListener(){

        public void onClick(View v) {

            milesToKilometers();
        }

       });


        mainButton2.setOnClickListener(new OnClickListener() {

            public void onClick(View v) {
                kilometersToMiles();
            }

        });

        back.setOnClickListener(new OnClickListener() {

            public void onClick(View v) {
                back();
                result.setText("");
                tkm.setText("");

            }

        });


    }


    protected void back() {

        main.setVisibility(View.VISIBLE);
        mainButton1.setVisibility(View.VISIBLE);
        mainButton2.setVisibility(View.VISIBLE);
        back.setVisibility(View.INVISIBLE);
        go.setVisibility(View.INVISIBLE);
        textbox.setVisibility(View.INVISIBLE);

    }


    protected void kilometersToMiles() {

        tkm.setText("Kilometers:");
        main.setVisibility(View.INVISIBLE);
        mainButton1.setVisibility(View.INVISIBLE);
        mainButton2.setVisibility(View.INVISIBLE);
        back.setVisibility(View.VISIBLE);
        go.setVisibility(View.VISIBLE);
        textbox.setVisibility(View.VISIBLE);
        go.setOnClickListener(new OnClickListener() {


            public void onClick(View v) {
                if(textbox.getText().toString().equals("")){

                    errors.setText("Error: Kilometers Missing");

                }
            }

        });
    }

    protected void milesToKilometers() {


        main.setVisibility(View.INVISIBLE);
        mainButton1.setVisibility(View.INVISIBLE);
        mainButton2.setVisibility(View.INVISIBLE);
        back.setVisibility(View.VISIBLE);
        go.setVisibility(View.VISIBLE);
        textbox.setVisibility(View.VISIBLE);

         go.setOnClickListener(new OnClickListener() {

                public void onClick(View v) {

                }

            });
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.activity_main, menu);
        return true;
    }


}

现在这里是logcat错误我不知道什么是错的...它对我没有任何意义。

08-18 15:54:14.687: E/AndroidRuntime(15778): Caused by: java.lang.ClassCastException: android.widget.TextView cannot be cast to android.widget.Button
08-18 15:54:14.687: E/AndroidRuntime(15778):    at k.t.m.MainActivity.onCreate(MainActivity.java:32)

感谢所有提前...这里是xml文件我不认为有什么不对，但是你去了......

<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" >

    <TextView
        android:id="@+id/main"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:text="                    What do you wish to convert?" />

    <Button
        android:id="@+id/mainButton2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="122dp"
        android:text="Kilometers to Miles" />

    <Button
        android:id="@+id/mainButton1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/mainButton2"
        android:layout_below="@+id/mainButton2"
        android:layout_marginTop="126dp"
        android:text="Miles to Kilometers" />

    <Button
        android:id="@+id/secondaryButtonBack"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/mainButton1"
        android:layout_marginTop="57dp"
        android:layout_toRightOf="@+id/mainButton1"
        android:text="Back" />

    <Button
        android:id="@+id/goButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/mainButton1"
        android:layout_centerHorizontal="true"
        android:text="Go" />

    <TextView
        android:id="@+id/result"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_centerVertical="true"
        android:text="" />

    <TextView
        android:id="@+id/errors"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/main"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="46dp"
        android:text="" />

    <EditText
        android:id="@+id/TextBox"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_above="@+id/result"
        android:layout_centerHorizontal="true"
        android:ems="10"
        android:inputType="number" />

    <TextView
        android:id="@+id/mkm"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_above="@+id/TextBox"
        android:layout_toLeftOf="@+id/result" />

</RelativeLayout>

这里是r.java我不知道该找什么，所以这里

/* AUTO-GENERATED FILE.  DO NOT MODIFY.
 *
 * This class was automatically generated by the
 * aapt tool from the resource data it found.  It
 * should not be modified by hand.
 */

package k.t.m;

public final class R {
    public static final class attr {
    }
    public static final class dimen {
        public static final int padding_large=0x7f040002;
        public static final int padding_medium=0x7f040001;
        public static final int padding_small=0x7f040000;
    }
    public static final class drawable {
        public static final int ic_action_search=0x7f020000;
        public static final int ic_launcher=0x7f020001;
    }
    public static final class id {
        public static final int TextBox=0x7f080008;
        public static final int errors=0x7f080007;
        public static final int goButton=0x7f080005;
        public static final int main=0x7f080000;
        public static final int mainButton1=0x7f080002;
        public static final int mainButton2=0x7f080001;
        public static final int menu_settings=0x7f080009;
        public static final int mkm=0x7f080004;
        public static final int result=0x7f080006;
        public static final int secondaryButtonBack=0x7f080003;
    }
    public static final class layout {
        public static final int activity_main=0x7f030000;
    }
    public static final class menu {
        public static final int activity_main=0x7f070000;
    }
    public static final class string {
        public static final int app_name=0x7f050000;
        public static final int hello_world=0x7f050001;
        public static final int menu_settings=0x7f050002;
        public static final int title_activity_main=0x7f050003;
    }
    public static final class style {
        public static final int AppTheme=0x7f060000;
    }
}

Answer 1

这意味着您必须修改findViewById。我认为在java代码中声明了一个textview，你将它引用到一个按钮id。请检查

Answer 2

我明白为什么你这么困惑......我唯一能想到的就是清理你的项目然后重建它。＆＃34;项目＆gt;清洁＆＃34;在日食。您可以在此搜索更多内容。但我现在感到困惑

Answer 3

清理项目并重建。确保重新生成R文件。有时Eclipse会让事情变得混乱

LogCat castExeption毫无意义

3 个答案: