ScrollView用法

最新推荐文章于 2025-05-10 09:49:20 发布

原创最新推荐文章于 2025-05-10 09:49:20 发布 · 139 阅读

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本文介绍了一个基于Android的示例项目，该项目展示了如何通过监听ScrollView的滚动事件来实现在LinearLayout中动态添加视图组件，并自动滚动到新添加的组件位置。文章详细解释了通过按钮点击事件来触发这一过程的方法。

package com.example.scrollview;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.os.Handler;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.ScrollView;
import android.widget.TextView;

public class MainActivity extends Activity {
	
	private ScrollView sView;
	private LinearLayout linearLayout;
	private Button button;
	private TextView textView;
	private Handler myHandler = new Handler();
	//当前滚屏的高度
	private int sHeight ;
	private Intent myIntent;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		sView = (ScrollView)findViewById(R.id.scrollView);
		linearLayout = (LinearLayout)findViewById(R.id.linearLayout);
		button = (Button)findViewById(R.id.button);
		textView = (TextView)findViewById(R.id.textView);
		sHeight = sView.getHeight();
		
		button.setOnClickListener(new myOnclickListener());
	}
	
	/**
	 * button事件：
	 * 1.点击button在linearlayout中动态添加textView和button
	 * 2.触发ScrollView的滚屏操作，滚动到最新添加的button处
	 *
	 */
	class myOnclickListener implements OnClickListener{

		int index = 0;
		
		@Override
		public void onClick(View v) {
			LinearLayout.LayoutParams linearLayoutParams = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT,
					LinearLayout.LayoutParams.WRAP_CONTENT);
			
			TextView addText = new TextView(MainActivity.this);
			addText.setText("textView"+index);
			
			Button addButton = new Button(MainActivity.this);
			addButton.setText("button"+index);
			addButton.setId(index++);

			linearLayout.addView(addText, linearLayoutParams);
			linearLayout.addView(addButton, linearLayoutParams);
		
			myHandler.post(mScrollToButton);
		}
		
	}
	
	private Runnable mScrollToButton = new Runnable() {
		
		@Override
		public void run() {
			
			//linearLayout的总高度
			System.out.println("linearLayout.getMeasuredHeight() =>"+linearLayout.getMeasuredHeight());
			//定位：位置 = 总高度 - 当前屏幕的高度
			int off = linearLayout.getMeasuredHeight() - sHeight;
			if(off > 0){
				//向下滚屏
				sView.scrollBy(0, off);
			}
			
		}
	};

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

}