Java 按下按钮时崩溃-未找到处理意图的活动

我是Android开发新手，我制作了一个简单的应用程序来计算体脂百分比，因为它工作得很好，但在我通过新的MainActivity并重写MainActivity.java的代码后，每次用户按下按钮，它都会出现错误，应用程序崩溃

MainActivity.java

package com.tech.syborg.bodyfat;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ImageButton;

import static com.tech.syborg.bodyfat.R.id.button3;

public class MainActivity extends AppCompatActivity {

private static Button button_cal;
private static Button button_how;

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


}

private void OnClickButtonListener() {
    button_cal = (Button)findViewById(R.id.button2);
    button_how = (Button)findViewById(R.id.button3);

    button_cal.setOnClickListener(
            new View.OnClickListener(){
                @Override
                public void onClick(View v){
                    Intent intent = new Intent("com.tech.syborg.bodyfat.GenderSelectActivity");
                    startActivity(intent);
                }
            }
    );
    button_how.setOnClickListener(
            new View.OnClickListener(){
                @Override
                public void onClick(View v){
                    Intent intent = new Intent("com.tech.syborg.bodyfat.HowToCalculateActivity");
                    startActivity(intent);
                }
            }
    );
}

}

manifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.tech.syborg.bodyfat">

<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:supportsRtl="true"
    android:theme="@style/AppTheme">

    <activity android:name=".MainActivity">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>

    <activity android:name=".GenderSelectActivity">
        <intent-filter>
            <action android:name="com.tech.syborg.bodyfat.GenderSelectActivity" />

            <category android:name="android.intent.category.DEFAULT" />
        </intent-filter>
    </activity>

    <activity android:name=".MaleCalculateActivity">
        <intent-filter>
            <action android:name="com.tech.syborg.bodyfat.MaleCalculateActivity" />

            <category android:name="android.intent.category.DEFAULT" />
        </intent-filter>
    </activity>

    <activity android:name=".FemaleCalculateActivity">
        <intent-filter>
            <action android:name="com.tech.syborg.bodyfat.FemaleCalculateActivity" />

            <category android:name="android.intent.category.DEFAULT" />
        </intent-filter>
    </activity>

    <activity android:name=".HowToCalculateActivity">
        <intent-filter>
            <action android:name="com.tech.syborg.bodyfat.HowToCalculateActivity" />

            <category android:name="android.intent.category.DEFAULT" />
        </intent-filter>
    </activity>

    <activity android:name=".ResultActivity">
        <intent-filter>
            <action android:name="com.tech.syborg.bodyfat.ResultActivity" />

            <category android:name="android.intent.category.DEFAULT" />
        </intent-filter>
    </activity>


    </activity>
</application>

---

更改

Intent Intent=新意图（“com.tech.syborg.bodyfat.genderselectivity”）

to

Intent Intent=new Intent（getApplicationContext（），GenderSelectActivity.class）

对于这个简单的应用程序，您只需要在MainActivity上使用

intent filter

，可能是我更改的代码的副本，但它不工作新错误-android.content.ActivityNotFoundException:找不到显式活动类{com.tech.syborg.bodyfat/com.tech.syborg.bodyfat.GenderSelectActivity}；您是否在AndroidManifest.xml中声明了此活动？

 <Button
    android:text="How To Take Measurements "
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:id="@+id/button3"
    android:textAppearance="?android:attr/textAppearanceSmall"
    android:background="?attr/colorPrimary"
    android:textColor="@android:color/white"
    android:layout_below="@+id/discription"
    android:layout_alignParentLeft="true"
    android:layout_alignParentStart="true"
    android:layout_marginTop="26dp" />

<Button
    android:text="  Calculate Body Fat %"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:id="@+id/button2"
    android:textAppearance="?android:attr/textAppearanceMedium"
    android:background="?attr/colorPrimary"
    android:textColor="@android:color/white"
    android:layout_below="@+id/button3"
    android:layout_alignParentLeft="true"
    android:layout_alignParentStart="true"
    android:layout_marginTop="36dp" />

02-12 19:52:14.536 5976-5976/? I/art: Late-enabling -Xcheck:jni
02-12 19:52:14.600 5976-5976/com.tech.syborg.bodyfat W/System:     ClassLoader referenced unknown path: /data/app/com.tech.syborg.bodyfat-1/lib/arm
02-12 19:52:14.611 5976-5976/com.tech.syborg.bodyfat I/InstantRun: Instant Run Runtime started. Android package is com.tech.syborg.bodyfat, real application class is null.
02-12 19:52:15.313 5976-5976/com.tech.syborg.bodyfat W/System: ClassLoader referenced unknown path: /data/app/com.tech.syborg.bodyfat-1/lib/arm
02-12 19:52:15.507 5976-5976/com.tech.syborg.bodyfat W/art: Before Android 4.1, method android.graphics.PorterDuffColorFilter android.support.graphics.drawable.VectorDrawableCompat.updateTintFilter(android.graphics.PorterDuffColorFilter, android.content.res.ColorStateList, android.graphics.PorterDuff$Mode) would have incorrectly overridden the package-private method in android.graphics.drawable.Drawable
02-12 19:52:15.907 5976-6242/com.tech.syborg.bodyfat I/Adreno: QUALCOMM build                   : 7d18700, I8ee426a9a2
                                                           Build Date                       : 10/07/16
                                                           OpenGL ES Shader Compiler Version: XE031.09.00.03
                                                           Local Branch                     : mybranch22308589
                                                           Remote Branch                    : quic/LA.BR.1.3.6_rb1.6
                                                           Remote Branch                    : NONE
                                                           Reconstruct Branch               : NOTHING
02-12 19:52:15.915 5976-6242/com.tech.syborg.bodyfat I/OpenGLRenderer: Initialized EGL, version 1.4
02-12 19:52:15.915 5976-6242/com.tech.syborg.bodyfat D/OpenGLRenderer: Swap behavior 1
02-12 19:52:18.524 5976-5976/com.tech.syborg.bodyfat D/AndroidRuntime: Shutting down VM
02-12 19:52:18.525 5976-5976/com.tech.syborg.bodyfat E/AndroidRuntime: FATAL EXCEPTION: main
                                                                   Process: com.tech.syborg.bodyfat, PID: 5976
                                                                   android.content.ActivityNotFoundException: No Activity found to handle Intent { act=com.tech.syborg.bodyfat.GenderSelectActivity }
                                                                       at android.app.Instrumentation.checkStartActivityResult(Instrumentation.java:1899)
                                                                       at android.app.Instrumentation.execStartActivity(Instrumentation.java:1589)
                                                                       at android.app.Activity.startActivityForResult(Activity.java:4228)
                                                                       at android.support.v4.app.BaseFragmentActivityJB.startActivityForResult(BaseFragmentActivityJB.java:50)
                                                                       at android.support.v4.app.FragmentActivity.startActivityForResult(FragmentActivity.java:79)
                                                                       at android.app.Activity.startActivityForResult(Activity.java:4187)
                                                                       at android.support.v4.app.FragmentActivity.startActivityForResult(FragmentActivity.java:859)
                                                                       at android.app.Activity.startActivity(Activity.java:4515)
                                                                       at android.app.Activity.startActivity(Activity.java:4483)
                                                                       at com.tech.syborg.bodyfat.MainActivity$1.onClick(MainActivity.java:35)
                                                                       at android.view.View.performClick(View.java:5612)
                                                                       at android.view.View$PerformClick.run(View.java:22285)
                                                                       at android.os.Handler.handleCallback(Handler.java:751)
                                                                       at android.os.Handler.dispatchMessage(Handler.java:95)
                                                                       at android.os.Looper.loop(Looper.java:154)
                                                                       at android.app.ActivityThread.main(ActivityThread.java:6123)
                                                                       at java.lang.reflect.Method.invoke(Native Method)
                                                                       at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:867)
                                                                       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:757)