Android studio 用控件TextView 添加图片

作业：用TextView 添加图片：创建一个按键，按键按下时就切换一张图片，总共有5张图片

1、在资源文件夹中加入图片

2、实现如下代码

public class MainActivity extends AppCompatActivity {
    TextView tx;
    Button bt1;
    int a;
    ImageSpan span1,span2,span3,span4,span5;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        tx = (TextView) findViewById(R.id.textView1);
        bt1 = (Button)findViewById(R.id.button);

        a= 1;
        span1 = new ImageSpan(this, R.mipmap.dangao1);
        span2 = new ImageSpan(this, R.mipmap.daogao2);
        span3 = new ImageSpan(this, R.mipmap.dangao3);
        span4 = new ImageSpan(this, R.mipmap.dangao4);
        span5 = new ImageSpan(this, R.mipmap.dangao5);

        SpannableString spanStr = new SpannableString(" ");
        spanStr.setSpan(span1, spanStr.length()-1, spanStr.length(), Spannable.SPAN_INCLUSIVE_EXCLUSIVE);
        tx.setText(spanStr );
        a++;
        bt1.setOnClickListener(listener1);//给BT1创建一个监听器}
    }
    Button.OnClickListener listener1 = new Button.OnClickListener(){//创建监听对象
        public void onClick(View v){
            //监听器里需要做的事
           if(a==2)
            {
                SpannableString spanStr = new SpannableString(" ");
                spanStr.setSpan(span2, spanStr.length()-1, spanStr.length(), Spannable.SPAN_INCLUSIVE_EXCLUSIVE);
                tx.setText(spanStr );
                a++;
            }
            else if(a==3)
            {
                SpannableString spanStr = new SpannableString(" ");
                spanStr.setSpan(span3, spanStr.length()-1, spanStr.length(), Spannable.SPAN_INCLUSIVE_EXCLUSIVE);
                tx.setText(spanStr );
                a++;
            }
            else if(a==4)
            {
                SpannableString spanStr = new SpannableString(" ");
                spanStr.setSpan(span4, spanStr.length()-1, spanStr.length(), Spannable.SPAN_INCLUSIVE_EXCLUSIVE);
                tx.setText(spanStr );
                a++;
            }
            else if(a==5)
            {
                SpannableString spanStr = new SpannableString(" ");
                spanStr.setSpan(span5, spanStr.length()-1, spanStr.length(), Spannable.SPAN_INCLUSIVE_EXCLUSIVE);
                tx.setText(spanStr );
                a++;
            }
            else if(a==6)
            {
                SpannableString spanStr = new SpannableString(" ");
                spanStr.setSpan(span1, spanStr.length()-1, spanStr.length(), Spannable.SPAN_INCLUSIVE_EXCLUSIVE);
                tx.setText(spanStr );
                a=2;
            }
        }
    };
}