Button next and prev not working

问题

This is my Linear Layout

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@android:color/white"
android:gravity="center_horizontal"
android:orientation="vertical" >

<AutoCompleteTextView
    android:id="@+id/autoCompleteTextView1"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_weight=".16"
    android:ems="10"
    android:text="Rule" >

    <requestFocus />
</AutoCompleteTextView>

<LinearLayout style="@style/verticallayout" >

    <LinearLayout style="@style/verticallayout" >

        <Button
            android:id="@+id/b1"
            style="@style/buttons"
            android:layout_weight=".16"
            android:text="Button 1" />
    </LinearLayout>

    <LinearLayout
        android:id="@+id/ll41"
        style="@style/horizontallayouthidden" >

        <TextView
            android:id="@+id/t1"
            style="@style/textview"
            android:layout_weight="0.5" />

        <TextView
            android:id="@+id/tt1"
            style="@style/textview"
            android:layout_weight="0.5" />
    </LinearLayout>
</LinearLayout>

<LinearLayout style="@style/verticallayout" >

    <LinearLayout style="@style/verticallayout" >

        <Button
            android:id="@+id/b2"
            style="@style/buttons"
            android:layout_weight=".16"
            android:text="Button 2" />
    </LinearLayout>

    <LinearLayout
        android:id="@+id/ll42"
        style="@style/horizontallayouthidden" >

        <TextView
            android:id="@+id/t2"
            style="@style/textview"
            android:layout_weight="0.5" />

        <TextView
            android:id="@+id/tt2"
            style="@style/textview"
            android:layout_weight="0.5" />
    </LinearLayout>
</LinearLayout>

<LinearLayout style="@style/verticallayout" >

    <LinearLayout style="@style/verticallayout" >

        <Button
            android:id="@+id/b3"
            style="@style/buttons"
            android:layout_weight=".16"
            android:text="Button 3" />
    </LinearLayout>

    <LinearLayout
        android:id="@+id/ll43"
        style="@style/horizontallayouthidden" >

        <TextView
            android:id="@+id/t3"
            style="@style/textview"
            android:layout_weight="0.5" />

        <TextView
            android:id="@+id/tt3"
            style="@style/textview"
            android:layout_weight="0.5" />
    </LinearLayout>
</LinearLayout>

<LinearLayout style="@style/verticallayout" >

    <LinearLayout style="@style/verticallayout" >

        <Button
            android:id="@+id/b4"
            style="@style/buttons"
            android:layout_weight=".16"
            android:text="Button 4" />
    </LinearLayout>

    <LinearLayout
        android:id="@+id/ll44"
        style="@style/horizontallayouthidden" >

        <TextView
            android:id="@+id/t4"
            style="@style/textview"
            android:layout_weight="0.5" />

        <TextView
            android:id="@+id/tt4"
            style="@style/textview"
            android:layout_weight="0.5" />
    </LinearLayout>
</LinearLayout>

<LinearLayout style="@style/verticallayout" >

    <LinearLayout style="@style/verticallayout" >

        <Button
            android:id="@+id/b5"
            style="@style/buttons"
            android:layout_weight=".16"
            android:text="Button 5" />
    </LinearLayout>

    <LinearLayout
        android:id="@+id/ll45"
        style="@style/horizontallayouthidden" >

        <TextView
            android:id="@+id/t5"
            style="@style/textview"
            android:layout_weight="0.5" />

        <TextView
            android:id="@+id/tt5"
            style="@style/textview"
            android:layout_weight="0.5" />
    </LinearLayout>
</LinearLayout>

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content" >

    <Button
        android:id="@+id/left"
        android:layout_width="wrap_content"
        android:layout_height="fill_parent"
        android:layout_weight="0.5"
        android:enabled="false"
        android:text="Prev" />

    <Button
        android:id="@+id/right"
        android:layout_width="wrap_content"
        android:layout_height="fill_parent"
        android:layout_weight="0.5"
        android:text="Next" />
</LinearLayout>

And this is my java Class

public void onClick(View arg0) {
    String a=null;
    switch(arg0.getId()){
    case R.id.left:
        Toast.makeText(getApplicationContext(), "Prev"+ count, Toast.LENGTH_LONG).show();
                    if( count==0)
        prev.setEnabled(false);
        else{
             count--;
            Toast.makeText(getApplicationContext(), "Prev", Toast.LENGTH_LONG).show();
        }
        break;
    case R.id.right:
        Toast.makeText(getApplicationContext(), "Prev"+ count, Toast.LENGTH_LONG).show();
        if( count>((abc.size()/5)))
            next.setEnabled(false);
        else{
             count++;
            onClick(arg0);
        }
        break;
    case R.id.b1:
        t41.setText("t1");
            tt41.setText("tt1");
            a=abc.get(( count*0)+0)+"";
            bb1.setText(a);
        }
        break;
    case R.id.b2:
        t42.setText("t1");
            tt42.setText("tt1");
            a=abc.get(( count*0)+1)+"";
            bb2.setText(a);
        }
        break;
    case R.id.b3:
        t43.setText("t1");
            tt43.setText("tt1");
            a=abc.get(( count*0)+2)+"";
            bb3.setText(a);
        }
        break;
    case R.id.b4:
        t44.setText("t1");
            tt44.setText("tt1");
            a=abc.get((count*0)+3)+"";
            bb4.setText(a);
        }
        break;
    case R.id.b5:
            t45.setText("t1");
            tt45.setText("tt1");
            a=abc.get((count*0)+4)+"";
            bb5.setText(a);
        }
        break;

    }
}

Now i want to change the text of button when i click the next and prev button dynamicaaly from a list that is available in list "abc". The count is STATIC variable in an other class. When i click the values are not changing in the button. Could anyone please help me out with this issue..

回答1:

You have not set onClick listeners to the buttons.

There are no views with id either "left" or "right"

In your xml give onClick attribute field to both buttons

I guess that will solve your problem.

回答2:

in your xml use this code wherever you want to call onClick() method

android:onClick="onClick"

for ex:

<Button
    android:id="@+id/left"
    android:layout_width="wrap_content"
    android:layout_height="fill_parent"
    android:layout_weight="0.5"
    android:enabled="false"
    android:text="Prev"
    android:onClick="onClick" />

<Button
    android:id="@+id/right"
    android:layout_width="wrap_content"
    android:layout_height="fill_parent"
    android:layout_weight="0.5"
    android:text="Next"
    android:onClick="onClick" />`

来源：https://stackoverflow.com/questions/14494574/button-next-and-prev-not-working