我正在尝试链接我的两个 Android 布局并进行处理。
MainActivity.java
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
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();
}
});
}
public void open(View view){
AlertDialog.Builder alb=new AlertDialog.Builder(this);
alb.setMessage("Are You Sure Do You Want This");
alb.setPositiveButton("yes", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
Toast.makeText(MainActivity.this,"You Clicked Yes Button",Toast.LENGTH_LONG).show();
}
});
alb.setNegativeButton("NO", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
Toast.makeText(MainActivity.this,"You Clicked Yes Button",Toast.LENGTH_LONG).show();
//finish();
}
});
AlertDialog al=alb.create();
al.show();
}
public void clockwise(View view){
ImageView iv=(ImageView) findViewById(R.id.imageView);
Animation animation = AnimationUtils.loadAnimation(getApplicationContext(),R.anim.myanimation);
iv.startAnimation(animation);
}
public void zoom(View view){
ImageView iv=(ImageView) findViewById(R.id.imageView);
Animation animation=AnimationUtils.loadAnimation(getApplicationContext(),R.anim.clockwise);
iv.startAnimation(animation);
}
public void fade(View view){
ImageView iv=(ImageView) findViewById(R.id.imageView);
Animation animation=AnimationUtils.loadAnimation(getApplicationContext(),R.anim.fade);
iv.startAnimation(animation);
}
public void blink(View view){
ImageView iv=(ImageView)findViewById(R.id.imageView);
Animation animation=AnimationUtils.loadAnimation(getApplicationContext(),R.anim.blink);
iv.startAnimation(animation);
}
public void move(View view){
ImageView iv=(ImageView)findViewById(R.id.imageView);
Animation animation=AnimationUtils.loadAnimation(getApplicationContext(),R.anim.move);
iv.startAnimation(animation);
}
public void slide(View view){
ImageView iv=(ImageView)findViewById(R.id.imageView);
Animation animation=AnimationUtils.loadAnimation(getApplicationContext(),R.anim.slide);
iv.startAnimation(animation);
}
public void next(View v){
// setContentView(R.layout.recording);
Intent inent = new Intent(this, RecordActivity.class);
startActivity(inent);
}
@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, 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);
}
}
RecordActivity.java
public class RecordActivity extends Activity {
private MediaRecorder mr;
Button play,record,stop;
private String outputFile=null;
@Override
public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.recording);
play=(Button)findViewById(R.id.button3);
stop=(Button)findViewById(R.id.button2);
record=(Button)findViewById(R.id.button);
stop.setEnabled(false);
play.setEnabled(false);
outputFile= Environment.getExternalStorageDirectory().getAbsolutePath()+"/recording.3gp";
mr=new MediaRecorder();
mr.setAudioSource(MediaRecorder.AudioSource.MIC);
mr.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
mr.setAudioEncoder(MediaRecorder.OutputFormat.AMR_NB);
mr.setOutputFile(outputFile);
}
public void Record(View v){
try{
mr.prepare();
mr.start();
}
catch (Exception e){
e.printStackTrace();
}
record.setEnabled(false);
stop.setEnabled(true);
}
public void stop(View v){
mr.stop();
mr.release();
mr=null;
stop.setEnabled(false);
play.setEnabled(true);
Toast.makeText(getApplicationContext(),"AudioRecorded Sucessfully",Toast.LENGTH_LONG);
}
public void play(View v){
MediaPlayer mp=new MediaPlayer();
try{
mp.setDataSource(outputFile);
mp.prepare();
}
catch (Exception e){
e.printStackTrace();
}
mp.start();
Toast.makeText(getApplicationContext(),"Playing Audio",Toast.LENGTH_LONG);
}
}
content_main.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
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"
app:layout_behavior="@string/appbar_scrolling_view_behavior"
tools:context="com.example.admin.alertapplication.MainActivity">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Alert Dialog"
android:id="@+id/textView"
android:textSize="35dp"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Raptor"
android:id="@+id/textView2"
android:textColor="#da644860"
android:textSize="35dp"
android:layout_below="@+id/textView"
android:layout_centerHorizontal="true" />
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/imageView"
android:src="@drawable/logo"
android:layout_below="@+id/textView2"
android:layout_alignLeft="@+id/textView"
android:layout_alignStart="@+id/textView"
android:layout_alignRight="@+id/button2"
android:layout_alignEnd="@+id/button2" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="zoom"
android:id="@+id/button"
android:layout_below="@+id/imageView"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_marginTop="40dp"
android:onClick="clockwise"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="clockwise"
android:id="@+id/button2"
android:layout_alignTop="@+id/button"
android:layout_centerHorizontal="true"
android:onClick="zoom"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="fade"
android:id="@+id/button3"
android:layout_alignTop="@+id/button2"
android:layout_alignParentRight="true"
android:layout_alignParentEnd="true"
android:onClick="fade"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="blink"
android:onClick="blink"
android:id="@+id/button4"
android:layout_below="@+id/button"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="move"
android:onClick="move"
android:id="@+id/button5"
android:layout_below="@+id/button2"
android:layout_alignRight="@+id/button2"
android:layout_alignEnd="@+id/button2"
android:layout_alignLeft="@+id/button2"
android:layout_alignStart="@+id/button2" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="slide"
android:onClick="slide"
android:id="@+id/button6"
android:layout_below="@+id/button3"
android:layout_toRightOf="@+id/textView"
android:layout_toEndOf="@+id/textView" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Next"
android:onClick="next"
android:id="@+id/button61"
android:layout_below="@+id/button4"
android:layout_alignRight="@+id/button4"
android:layout_alignEnd="@+id/button4" />
</RelativeLayout>
recording.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin"
android:weightSum="1">
<TextView
android:layout_width="234dp"
android:layout_height="112dp"
android:text="Android Audio Recording"
android:id="@+id/textView3"
android:layout_gravity="center_horizontal"
android:textSize="30dp"
android:textColor="#d50c0c"
android:layout_weight="0.01" />
<ImageView
android:layout_width="wrap_content"
android:layout_height="86dp"
android:id="@+id/imageView2"
android:src="@drawable/logo"
android:layout_gravity="center_horizontal"
/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Record"
android:id="@+id/button7"
android:layout_below="@+id/imageView2"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_marginTop="59dp"
android:onClick="Record"
/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Stop"
android:id="@+id/button8"
android:layout_alignTop="@+id/button"
android:layout_centerHorizontal="true"
android:layout_gravity="center_horizontal"
android:onClick="stop"
/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="play"
android:id="@+id/button9"
android:layout_alignTop="@+id/button8"
android:layout_alignRight="@+id/textView3"
android:layout_alignEnd="@+id/textView3"
android:layout_gravity="right"
android:onClick="play"
/>
</LinearLayout>
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.admin.alertapplication">
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.RECORD_AUDIO"/>
<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"
android:label="@string/app_name"
android:theme="@style/AppTheme.NoActionBar">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".RecordActivity"
android:label="@string/app_name"
android:theme="@style/AppTheme.NoActionBar">
<intent-filter>
<action android:name="android.intent.action.VIEW" />
</intent-filter>
</activity>
</application>
</manifest>
stack trace 04-22 14:24:09.415 4470-4470/com.example.admin.alertapplication E/AndroidRuntime: FATAL EXCEPTION: main Process: com.example.admin.alertapplication, PID: 4470 java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.admin.alertapplication/com.example.admin.alertapplication.RecordActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Button.setEnabled(boolean)' on a null object reference at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2325) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387) at android.app.ActivityThread.access$800(ActivityThread.java:151) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:135) at android.app.ActivityThread.main(ActivityThread.java:5254) at java.lang.reflect.Method.invoke(Native Method) at java.lang.reflect.Method.invoke(Method.java:372) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698) Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Button.setEnabled(boolean)' on a null object reference at com.example.admin.alertapplication.RecordActivity.onCreate(RecordActivity.java:27) at android.app.Activity.performCreate(Activity.java:5990) at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106) at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2278) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387) at android.app.ActivityThread.access$800(ActivityThread.java:151) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:135) at android.app.ActivityThread.main(ActivityThread.java:5254) at java.lang.reflect.Method.invoke(Native Method) at java.lang.reflect.Method.invoke(Method.java:372) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
我正在使用上面的代码在单击下一个按钮时链接两个布局 next() 函数将在此之后调用 不幸的是应用程序已停止为什么会这样谁能帮我解决这个问题
最佳答案
原因是在RecordActivity这一行
play=(Button)findViewById(R.id.button3);
因为 recording.xml 不包含 button3 所以 play(Button) 将是 null
然后你调用 play.setEnabled(false); => 你的应用因 NullPointerException
关于java - 在android中链接两个布局，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/36789161/