Question

嗨我想从同一版面的文本视图自动向下滚动到文本视图，但它给我错误请找出我错误的错误。我的代码。我希望当我点击id“Signandsymptoms”的文本视图时，它会直接向下滚动到“Signandsymptomsparagragh”的ID。

错误日志：

01-28 15:22:39.929: E/AndroidRuntime(18673): FATAL EXCEPTION: main
01-28 15:22:39.929: E/AndroidRuntime(18673): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.kmcpesh.shortreviewofcardiology/com.kmcpesh.shortreviewofcardiology.Atherosclerosis}: java.lang.NullPointerException
01-28 15:22:39.929: E/AndroidRuntime(18673):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2219)
01-28 15:22:39.929: E/AndroidRuntime(18673):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2349)
01-28 15:22:39.929: E/AndroidRuntime(18673):    at android.app.ActivityThread.access$700(ActivityThread.java:159)
01-28 15:22:39.929: E/AndroidRuntime(18673):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1316)
01-28 15:22:39.929: E/AndroidRuntime(18673):    at android.os.Handler.dispatchMessage(Handler.java:99)
01-28 15:22:39.929: E/AndroidRuntime(18673):    at android.os.Looper.loop(Looper.java:137)
01-28 15:22:39.929: E/AndroidRuntime(18673):    at android.app.ActivityThread.main(ActivityThread.java:5419)
01-28 15:22:39.929: E/AndroidRuntime(18673):    at java.lang.reflect.Method.invokeNative(Native Method)
01-28 15:22:39.929: E/AndroidRuntime(18673):    at java.lang.reflect.Method.invoke(Method.java:525)
01-28 15:22:39.929: E/AndroidRuntime(18673):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1187)
01-28 15:22:39.929: E/AndroidRuntime(18673):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1003)
01-28 15:22:39.929: E/AndroidRuntime(18673):    at dalvik.system.NativeStart.main(Native Method)
01-28 15:22:39.929: E/AndroidRuntime(18673): Caused by: java.lang.NullPointerException
01-28 15:22:39.929: E/AndroidRuntime(18673):    at android.app.Activity.findViewById(Activity.java:1914)
01-28 15:22:39.929: E/AndroidRuntime(18673):    at com.kmcpesh.shortreviewofcardiology.Atherosclerosis.<init>(Atherosclerosis.java:24)
E/AndroidRuntime(18673):    at java.lang.Class.newInstanceImpl(Native Method)
01-28 15:22:39.929: E/AndroidRuntime(18673):    at java.lang.Class.newInstance(Class.java:1130)
01-28 15:22:39.929: E/AndroidRuntime(18673):    at android.app.Instrumentation.newActivity(Instrumentation.java:1078)
01-28 15:22:39.929: E/AndroidRuntime(18673):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2210)

import android.os.Build;
import android.os.Bundle;
import android.os.CountDownTimer;
import android.annotation.SuppressLint;
import android.annotation.TargetApi;
import android.app.ActionBar;
import android.app.Activity;
import android.content.Intent;
import android.graphics.Color;
import android.graphics.drawable.ColorDrawable;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.ScrollView;
import android.widget.TextView;

@TargetApi(Build.VERSION_CODES.HONEYCOMB)
@SuppressLint("NewApi")
public class Atherosclerosis extends Activity {
ScrollView scrollView=(ScrollView)findViewById(R.id.scrollatherosclerosis);
TextView tv=(TextView)findViewById(R.id.Signandsymptompsid);
TextView tvabove=(TextView)findViewById(R.id.Signandsymptomsparagraph);
    @TargetApi(Build.VERSION_CODES.HONEYCOMB)
    @SuppressLint("NewApi")
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.atherosclerosis);
         ActionBar bar = getActionBar();
            bar.setBackgroundDrawable(new ColorDrawable(Color.parseColor("#6B8E23")));
            getActionBar().setDisplayHomeAsUpEnabled(true);
            getActionBar().setHomeButtonEnabled(true); 

            tv.setOnClickListener(new View.OnClickListener() {

                @Override
                public void onClick(View v) {
                    // TODO Auto-generated method stub
                    scrollView.post(
                            new Runnable() {
                                @Override
                                public void run() {
                                    new CountDownTimer(1500, 20) {
                                        @Override
                                        public void onTick(long millisUntilFinished) {
                                            scrollView.scrollTo(0, (int) (tvabove.getBottom()-millisUntilFinished));
                                        }

                                       @Override
                                       public void onFinish() {                 
                                       }
                                    }.start();
                                }
                            }
                        );
                }
            });

    }
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.atherosclerosis, menu);
        return true;
    }
      @Override
        public boolean onOptionsItemSelected(MenuItem item) {
            // Take appropriate action for each action item click
            switch (item.getItemId()) {
            case R.id.id_search:
                Intent newActivity0 = new Intent(this,Search.class);     
                 startActivity(newActivity0);
                return true;
            case R.id.id_favorit:
               return true;

            default:
                return super.onOptionsItemSelected(item);
            }
        }
}

我的.XML布局

<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:background="#ffffff"
    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=".Atherosclerosis"
    tools:ignore="UselessParent,ScrollViewCount" >
<ScrollView
    android:id="@+id/scrollatherosclerosis"
    android:layout_width="match_parent"
    android:layout_height="wrap_content" >
    <RelativeLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content">
<LinearLayout
     android:id="@+id/tablecontentlayout"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    android:background="#EFECCB" >
    <TextView
        android:layout_marginLeft="10dp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="17sp"
        android:textStyle="bold"
        android:textColor="#000000"
        android:text="@string/table" />
     <TextView
         android:id="@+id/definitionid"
         android:layout_marginLeft="10dp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="16sp"
        android:textStyle="bold"
        android:textColor="#4682B4"
        android:text="@string/Definition" />
     <TextView
         android:layout_marginLeft="10dp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="16sp"
        android:textStyle="bold"
        android:textColor="#4682B4"
        android:text="@string/RiskFactors" />
      <TextView
          android:id="@+id/pathophysiology_id"
          android:layout_marginLeft="10dp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="16sp"
        android:textStyle="bold"
        android:textColor="#4682B4"
        android:text="@string/Pathophysiology" />
      <TextView
          android:id="@+id/Signandsymptompsid"
          android:layout_marginLeft="10dp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="16sp"
        android:textStyle="bold"
        android:textColor="#4682B4"
        android:text="@string/SignsandSymptoms" />
       <TextView
           android:layout_marginLeft="10dp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="16sp"
        android:textStyle="bold"
        android:textColor="#4682B4"
        android:text="@string/Diagnosis" />
       <TextView
           android:layout_marginLeft="10dp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="16sp"
        android:textStyle="bold"
        android:textColor="#4682B4"
        android:text="@string/Treatment" />
       <TextView
           android:layout_marginLeft="10dp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="16sp"
        android:textStyle="bold"
        android:textColor="#4682B4"
        android:text="@string/Prevention" />
       <TextView
           android:layout_marginLeft="10dp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="16sp"
        android:textStyle="bold"
        android:textColor="#4682B4"
        android:text="@string/Complications" />
    </LinearLayout>
    <LinearLayout
        android:layout_width="match_parent"
    android:layout_height="wrap_content"

    android:layout_below="@+id/tablecontentlayout"
    android:layout_marginTop="15dp"
    android:orientation="vertical" >
        <TextView
            android:id="@+id/atherodefinition" 
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="@string/Definition"
            android:background="#F5F5F5"
            android:textColor="#264177"
            android:textSize="17sp"
            android:textStyle="bold"/>
        <TextView 
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="@string/atherosclerosisdefinition"
            android:textSize="15sp"/>
          <TextView

            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="@string/RiskFactors"
            android:background="#F5F5F5"
            android:textColor="#264177"
            android:textSize="17sp"
            android:textStyle="bold"/>
        <TextView 
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="@string/Modifiable"
            android:textStyle="bold"
            android:textSize="15sp"/>
        <TextView 
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="@string/modifiableatherosclerosis"
            android:textSize="15sp"/>
        <TextView 
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="@string/Nonmodifiable"
            android:textStyle="bold"
            android:textSize="15sp"/>
        <TextView 
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="@string/nonmodifiableatherosclerosis"
            android:textSize="15sp"/>
          <TextView

            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="@string/Pathophysiology"
            android:background="#F5F5F5"
            android:textColor="#264177"
            android:textSize="17sp"
            android:textStyle="bold"/>
        <TextView 
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="@string/pathophysiologyatherosclerosis"
            android:textSize="15sp"/>
        <TextView
            android:id="@+id/Signandsymptomsparagraph"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="@string/SignsandSymptoms"
            android:background="#F5F5F5"
            android:textColor="#264177"
            android:textSize="17sp"
            android:textStyle="bold"/>
         <TextView 
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="@string/atherosclerosissignsandsymptoms"
            android:textSize="15sp"/>
         <TextView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="@string/Diagnosis"
            android:background="#F5F5F5"
            android:textColor="#264177"
            android:textSize="17sp"
            android:textStyle="bold"/>
         <TextView 
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="@string/Diagnosisatherosclerosis"
            android:textSize="15sp"/>
         <TextView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="@string/Treatment"
            android:background="#F5F5F5"
            android:textColor="#264177"
            android:textSize="17sp"
            android:textStyle="bold"/>
         <TextView 
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="@string/lifestylemodification"
            android:textSize="15sp"/>
         <TextView 
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="@string/treatmentatherosclerosis"
            android:textSize="15sp"/>
         <TextView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="@string/Prevention"
            android:background="#F5F5F5"
            android:textColor="#264177"
            android:textSize="17sp"
            android:textStyle="bold"/>
         <TextView 
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="@string/Preventionatherosclerosis"
            android:textSize="15sp"/>
         <TextView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="@string/Complications"
            android:background="#F5F5F5"
            android:textColor="#264177"
            android:textSize="17sp"
            android:textStyle="bold"/>
         <TextView 
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="@string/complicationatherosclerosis"
            android:textSize="15sp"/>
    </LinearLayout>
    </RelativeLayout>
    </ScrollView>

</RelativeLayout>

Answer 1

我认为如果你在onCreate（）方法中调用findViewById（）就解决了你的问题：

private ScrollView scrollView;
private TextView tvabove;
private TextView tv;
....
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_dragpanel);
    scrollView = (ScrollView)findViewById(R.id.scrollatherosclerosis);
    tv = (TextView)findViewById(R.id.Signandsymptompsid);
    tvabove = (TextView)findViewById(R.id.Signandsymptomsparagraph);
    ...
}

从TextView单击向下滚动到TextView

1 个答案: