Listview not displaying min and max values in Range seek bar

问题

I wanted to create a seeker bar with 2 thumbs and a textview showing the min and max value. Therefore i refer to this tutorial https://code.google.com/p/range-seek-bar/#Example_usage_as_Integer_range?.

However, during runtime, the textview does not change when the thumbs is being dragged. My project is made up of 2 java activity. Main activity as attached below and RangeSeekBar.java which is exactly the same as in the tutorial.Kindly seek your advice.

MainActivity.java

package com.example.doubleseekbar;


import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.ViewGroup;
import android.widget.TextView;

import com.example.gto_doubleseekbar.RangeSeekBar.OnRangeSeekBarChangeListener;

public class MainActivity extends Activity {

    private TextView textview;
    protected static final String TAG = "com.example.doubleseekbar";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        textview = (TextView) findViewById(R.id.textView1);

        // create RangeSeekBar as Integer range between 20 and 75
        RangeSeekBar<Integer> seekBar = new RangeSeekBar<Integer>(20, 75, this);

        seekBar.setOnRangeSeekBarChangeListener(new OnRangeSeekBarChangeListener<Integer>() {
                @Override
                public void onRangeSeekBarValuesChanged(RangeSeekBar<?> bar, Integer minValue, Integer maxValue) {
                        // handle changed range values
                    String powerranger = "User selected new range values: MIN=" + minValue + ", MAX=" + maxValue;
                    Log.i(TAG, powerranger);
                    textview.setText(powerranger);

                }
        });

        // add RangeSeekBar to pre-defined layout
        LayoutInflater inflater = (LayoutInflater)getApplicationContext().getSystemService
                (Context.LAYOUT_INFLATER_SERVICE);
        ViewGroup layout = (ViewGroup) inflater.inflate(R.layout.activity_main,null);
        layout.addView(seekBar);
        setContentView(layout);

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

}

activity_main.xml

<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: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=".MainActivity" >

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:layout_marginTop="193dp"
        android:text="Range value to be change here" />

</RelativeLayout>

Really grateful for your feedback.

回答1:

->Give id your activity_main.xml 
-> setContentView(layout) why you are calling two times ?? Remove these line from your                    
   code so your code should look like below

activity_main.xml

<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:id="@+id/root_view"   ----->>this is id of your main layout
    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=".MainActivity" >

      <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:layout_marginTop="193dp"
        android:text="Range value to be change here" />
       </RelativeLayout>

In MainActivity.java

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

        // create RangeSeekBar as Integer range between 20 and 75
        RangeSeekBar<Integer> seekBar = new RangeSeekBar<Integer>(20, 75, this);
        seekBar.setOnRangeSeekBarChangeListener(new OnRangeSeekBarChangeListener<Integer>() {
            @Override
            public void onRangeSeekBarValuesChanged(RangeSeekBar<?> bar,
                    Integer minValue, Integer maxValue) {
                  // handle changed range values
                 String powerranger = "User selected new range values: MIN=" + minValue + ", MAX=" + maxValue;
                  //Log.i(TAG, powerranger);
                 textView1.setText(powerranger);
            }
        });

        // add RangeSeekBar to pre-defined layout
        ViewGroup layout = (ViewGroup) findViewById(R.id.root_view);
        layout.addView(seekBar);
    }

来源：https://stackoverflow.com/questions/21759626/listview-not-displaying-min-and-max-values-in-range-seek-bar