ch08.rar

package com.ehappy.excontextmenu; import android.graphics.Color; import android.os.Bundle; import androidx.appcompat.app.AppCompatActivity; import androidx.appcompat.widget.Toolbar; import androidx.constraintlayout.widget.ConstraintLayout; import android.view.ContextMenu; import android.view.View; import android.view.Menu; import android.view.MenuItem; import android.widget.TextView; public class MainActivity extends AppCompatActivity { ConstraintLayout myLayout; TextView txtShow1; TextView txtShow2; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar); setSupportActionBar(toolbar); myLayout=(ConstraintLayout)findViewById(R.id.myLayout); txtShow1=(TextView)findViewById(R.id.txtShow1); txtShow2=(TextView)findViewById(R.id.txtShow2); registerForContextMenu(txtShow1); registerForContextMenu(txtShow2); } protected static final int MENU_BLACKCOLOR = Menu.FIRST ; protected static final int MENU_WHITECOLOR = Menu.FIRST +1; protected static final int MENU_SMALLSIZE = Menu.FIRST +2; protected static final int MENU_LARGESIZE = Menu.FIRST +3; @Override public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) { super.onCreateContextMenu(menu, v, menuInfo); if (v==txtShow1){ menu.add(0,MENU_BLACKCOLOR ,1,"黑色背景顏色"); menu.add(0,MENU_WHITECOLOR ,2,"白色背景顏色"); } else if (v==txtShow2){ menu.add(0,MENU_SMALLSIZE ,1,"較小字體"); menu.add(0,MENU_LARGESIZE ,2,"較大字體"); } } @Override public boolean onContextItemSelected(MenuItem item) { switch (item.getItemId()){ case MENU_BLACKCOLOR: myLayout.setBackgroundColor(Color.BLACK); break; case MENU_WHITECOLOR: myLayout.setBackgroundColor(Color.WHITE); break; case MENU_SMALLSIZE: txtShow1.setTextSize(14); txtShow2.setTextSize(14); break; case MENU_LARGESIZE: txtShow1.setTextSize(24); txtShow2.setTextSize(24); break; } return super.onContextItemSelected(item); } }